By utilizing the fluctuation exchange approximation method,we perform a study on the superconducting pairing symmetry in a t_(2g) three-orbital model on the square lattice.Although the tight-binding parameters of the ...By utilizing the fluctuation exchange approximation method,we perform a study on the superconducting pairing symmetry in a t_(2g) three-orbital model on the square lattice.Although the tight-binding parameters of the model are based on Sr_(2)RuO_(4),we have systematically studied the evolution of superconducting pairing symmetry with the carrier density and interactions,making our findings relevant to a broader range of material systems.Under a moderate Hund’s coupling,we find that spin fluctuations dominate the superconducting pairing,leading to a prevalent spin-singlet pairing with a d_(x^(2)-y^(2))-wave symmetry for the carrier density within the range of n=1.5-4 per site.By reducing the Hund’s coupling,the charge fluctuations are enhanced and play a crucial role in determining the pairing symmetry,leading to a transition of the pairing symmetry from the spin-singlet d_(x^(2)-y^(2))-wave to the spin-triplet p-wave.Furthermore,we find that the superconducting pairings are orbital dependent.As the carrier density changes from n=4 to n=1.5,the active orbitals for superconducting pairing shift from the quasi-two-dimensional orbital dxy to the quasi-one-dimensional orbitals d_(xz) and d_(yz).展开更多
Recent theory and experiments show that artificial magnetic skyrmions can be stabilized at room temperature without the need for the external magnetic field,casting strong potentials for the device applications.In thi...Recent theory and experiments show that artificial magnetic skyrmions can be stabilized at room temperature without the need for the external magnetic field,casting strong potentials for the device applications.In this work,we study the electric field manipulation of artificial magnetic skyrmions imprinted by Co disks on CoPt multilayers utilizing the micromagnetic simulations.We find that the reversible annihilation and creation of skyrmions can be realized with the electric field via the strain mediated magnetoelastic coupling.In addition,we also demonstrate controllable manipulation of individual skyrmion,which opens a new platform for constructing magnetic field-free and low-energy dissipation skyrmion based media.展开更多
The discovery of high-temperature superconductivity near 80K in bilayer nickelate La_(3)Ni_(2)O_(7)under high pressures has renewed the exploration of superconducting nickelate in bulk materials.The extension of super...The discovery of high-temperature superconductivity near 80K in bilayer nickelate La_(3)Ni_(2)O_(7)under high pressures has renewed the exploration of superconducting nickelate in bulk materials.The extension of superconductivity in other nickelates in a broader family is also essential.Here,we report the experimental observation of superconducting signature in trilayer nickelate La_(4)Ni_(3)O_(10)under high pressures.By using a modified solgel method and post-annealing treatment under high oxygen pressure,we successfully obtained polycrystalline La_(4)Ni_(3)O_(10)samples with different transport behaviors at ambient pressure.Then we performed high-pressure electrical resistance measurements on these samples in a diamond-anvil-cell apparatus.Surprisingly,the signature of possible superconducting transition with a maximum transition temperature(T_(c))of about 20K under high pressures is observed,as evidenced by a clear drop of resistance and the suppression of resistance drops under magnetic fields.Although the resistance drop is sample-dependent and relatively small,it appears in all of our measured samples.We argue that the observed superconducting signal is most likely to originate from the main phase of La_(4)Ni_(3)O_(10).Our findings will motivate the exploration of superconductivity in a broader family of nickelates and shed light on the understanding of the underlying mechanisms of high-T_(c) superconductivity in nickelates.展开更多
We successfully grow a new superconductor GaBa2Ca3Cu4O11+δ(Ga-1234) with a transition temperature of 113 K, using the Walker-type high-pressure synthesis apparatus. X-ray diffraction measurements on the powderized sa...We successfully grow a new superconductor GaBa2Ca3Cu4O11+δ(Ga-1234) with a transition temperature of 113 K, using the Walker-type high-pressure synthesis apparatus. X-ray diffraction measurements on the powderized samples show a mixture of the Ga-1234 phase and the Ca0.85CuO2phase, and the former is dominant. Under the scanning electron microscope, plate-like crystals of the Ga-based 1234 phase with shiny surfaces can be seen.The obtained local chemical compositions revealed by energy dispersion x-ray spectroscopy are very close to the stoichiometric values. On some sub-millimeter crystal-like samples of the 1234 phase, we obtain a full Meissner shielding volume. From the temperature-dependent magnetizations, we determine the irreversibility fields and find that the system exhibits a highly anisotropic behavior.展开更多
We investigate the structural,static magnetic and damping properties in two Mn-deficient magnetic Weyl semimetal Co-Mn-Ga(CMG) alloy films,i.e.,Co_(55)Mn_(18)Ga_(27)(CMG1) and Co_(50)Mn_(18)Ga_(32)(CMG2),which were ep...We investigate the structural,static magnetic and damping properties in two Mn-deficient magnetic Weyl semimetal Co-Mn-Ga(CMG) alloy films,i.e.,Co_(55)Mn_(18)Ga_(27)(CMG1) and Co_(50)Mn_(18)Ga_(32)(CMG2),which were epitaxially grown on MgO(001) substrates.CMG1 has a mixing phase of B2and L21,larger saturation magnetization(M_(s) ~760 emu/cm^(3)),stronger in-plane magnetic anisotropy.CMG2 has an almost pure B2phase,smaller M_(s)(~330 emu/cm^(3)),negligible in-plane magnetic anisotropy.Time-resolved magneto-optical Kerr effect results unambiguously demonstrate an obvious perpendicular standing spin wave(PSSW) mode in addition to the Kittel mode for both of the CMG films.The intrinsic damping constant is about 0.0055 and 0.015 for CMG1 and CMG2,respectively,which are both significantly larger than that of the stoichiometric CMG(i.e.,Co_(2)MnGa)film reported previously.In combination with the first-principles calculations,the intrinsic damping properties of the Mn-deficient CMG films can be well explained by considering the increase of density of states at the Fermi level,reduction of M_(s),and excitation of the PSSW mode.These findings provide a new clue to tuning the magnetic damping of the magnetic Weyl semimetal film through slight off-stoichiometry.展开更多
This paper studies the normal state properties of itinerant electrons in a toy model,which is constructed according to the model for coexisting ferromagnetism and superconductivity proposed by Suhl [Suhl H 2001 Phys.R...This paper studies the normal state properties of itinerant electrons in a toy model,which is constructed according to the model for coexisting ferromagnetism and superconductivity proposed by Suhl [Suhl H 2001 Phys.Rev.Lett.87 167007].In this theory with ferromagnetic ordering based on localized spins,the exchange interaction J between conduction electrons and localized spin is taken as the pairing glue for s-wave superconductivity.It shows that this J term will first renormalize the normal state single conduction electron structures substantially.It finds dramatically enhanced or suppressed magnetization of itinerant electrons for positive or negative J.Singlet Cooper pairing can be ruled out due to strong spin polarisation in the J > 0 case while a narrow window for s-wave superconductivity is opened around some ferromagnetic J.展开更多
Electric-field control of perpendicular magnetic anisotropy(PMA) is a feasible way to manipulate perpendicular magnetization,which is of great importance for realizing energy-efficient spintronics.Here,we propose a no...Electric-field control of perpendicular magnetic anisotropy(PMA) is a feasible way to manipulate perpendicular magnetization,which is of great importance for realizing energy-efficient spintronics.Here,we propose a novel approach to accomplish this task at room temperature by resistive switching(RS) via electrochemical metallization(ECM) in a device with the stack of Si/SiO_(2)/Ta/Pt/Ag/Mn-doped ZnO(MZO)/Pt/Co/Pt/ITO.By applying certain voltages,the device could be set at high-resistance-state(HRS) and low-resistance-state(LRS),accompanied with a larger and a smaller coercivity(H_(C)),respectively,which demonstrates a nonvolatile E-field control of PMA.Based on our previous studies and the present control experiments,the electric modulation of PMA can be briefly explained as follows.At LRS,the Ag conductive filaments form and pass through the entire MZO layer and finally reach the Pt/Co/Pt sandwich,leading to weakening of PMA and reduction of H_(C).In contrast,at HRS,most of the Ag filaments dissolve and leave away from the Pt/Co/Pt sandwich,causing partial recovery of PMA and an increase of H_(C).This work provides a new clue to designing low-power spintronic devices based on PMA films.展开更多
In this paper, we use a molecular theory to study the anomalous switching of ss DNA monolayers. Here, both ss DNA–water and water–water hydrogen bonds and their explicit coupling to the ss DNA conformations are cons...In this paper, we use a molecular theory to study the anomalous switching of ss DNA monolayers. Here, both ss DNA–water and water–water hydrogen bonds and their explicit coupling to the ss DNA conformations are considered. We find that hydrogen bonding becomes a key element in inducing the anomalous switching of ss DNA monolayers. This finding accords well with the experimental observations. Based on our theoretical model, we predict that the anomalous switching induced by water vapor will be applicable to a wide range of hydrogen bonds polymers, and ss DNA–water hydrogen bonds and water–water hydrogen bonds hybridization will lead to the hydrogen-bond network formation of 3D ss DNA monolayers.展开更多
We study the motion of a hole with internal degrees of freedom,introduced to the zigzag magnetic ground state of Na_(2)IrO_(3),by using the self-consistent Born approximation.We find that the low-,intermediate-,and hi...We study the motion of a hole with internal degrees of freedom,introduced to the zigzag magnetic ground state of Na_(2)IrO_(3),by using the self-consistent Born approximation.We find that the low-,intermediate-,and high-energy spectra are primarily attributed to the singlet,triplet,and quintet hole contributions,respectively.The spectral functions exhibit distinct features such as the electron-like dispersion of low-energy states near the L point,the maximum M-point intensity of mid-energy states,and the hole-like dispersion of high-energy states.These features are robust and almost insensitive to the exchange model and Hund's coupling,and are in qualitative agreement with the angular-resolved photoemission spectra observed in Na_(2)IrO_(3).Our results reveal that the interference between internal degrees of freedom in different sublattices plays an important role in inducing the complex dispersions.展开更多
Using a molecular theory, we investigate the temperature-dependent self-assembly of single-stranded DNA(ss DNA)tethered to a charged nanoparticle surface. Here the size, conformations, and charge properties of ss DNA ...Using a molecular theory, we investigate the temperature-dependent self-assembly of single-stranded DNA(ss DNA)tethered to a charged nanoparticle surface. Here the size, conformations, and charge properties of ss DNA are taken into account. The main results are as follows: i) when the temperature is lower than the critical switching temperature, the ss DNA will collapse due to the existence of electrostatic interaction between ss DNA and charged nanoparticle surface; ii)for the short ss DNA chains with the number of bases less than 10, the switching of ss DNA cannot happen, and the critical temperature does not exist; iii) when the temperature increases, the electrostatic attractive interaction between ss DNA and charged nanoparticle surface becomes weak dramatically, and ss DNA chains will stretch if the electrostatic attractive interaction is insufficient to overcome the elastic energy of ss DNA and the electrostatic repulsion energy. These findings accord well with the experimental observations. It is predicted that the switching of ss DNA will not happen if the grafting densities are too high.展开更多
Tuning magnetic damping constant in dedicated spintronic devices has important scientific and technological implications. Here we report on anisotropic damping in various compositional amorphous CoFeB films grown on G...Tuning magnetic damping constant in dedicated spintronic devices has important scientific and technological implications. Here we report on anisotropic damping in various compositional amorphous CoFeB films grown on GaAs(001) substrates. Measured by a vector network analyzer-ferromagnetic resonance (VNA-FMR) equipment, a giant magnetic damping anisotropy of 385%, i.e., the damping constant increases by about four times, is observed in a 10-nm-thick Co40Fe40B20 film when its magnetization rotates from easy axis to hard axis, accompanied by a large and pure in-plane uniaxial magnetic anisotropy (UMA) with its anisotropic field of about 450 Oe. The distinct damping anisotropy is mainly resulted from anisotropic two-magnon-scattering induced by the interface between the ferromagnetic layer and the substrate, which also generates a significant UMA in the film plane.展开更多
The charge-storage characteristics of charge trapping memory devices containing different sizes of Au nanocrystals(NCs)sandwiched by Al2O3 tunneling and blocking layers are studied.A strong impact of both Au NC size a...The charge-storage characteristics of charge trapping memory devices containing different sizes of Au nanocrystals(NCs)sandwiched by Al2O3 tunneling and blocking layers are studied.A strong impact of both Au NC size and inter-NC distance on the charge trapping capability of the devices is observed.The total surface area of Au NCs associated with Au NC size is supposed to be a key factor in the charge-storage capability,and the device with larger size of Au NCs and a suitable inter-NC distance will possess better charge trapping capability.Variable range hopping as the lateral charge loss mechanism is considered as the main reason for the decrease of the charge trapping capability when Au NCs grow and overlap neighbors.展开更多
Recently,lipid nanoparticles(LNPs)have been extensively investigated as non-viral carriers of nucleic acid vaccines due to their high transport efficiency,safety,and straightforward production and scalability.However,...Recently,lipid nanoparticles(LNPs)have been extensively investigated as non-viral carriers of nucleic acid vaccines due to their high transport efficiency,safety,and straightforward production and scalability.However,the molecular mechanism underlying the interactions between nucleic acids and phospholipid bilayers within LNPs remains elusive.In this study,we employed the all-atom molecular dynamics simulation to investigate the interactions between single-stranded nucleic acids and a phospholipid bilayer.Our findings revealed that hydrophilic bases,specifically G in single-stranded RNA(ssRNA)and single-stranded DNA(ssDNA),displayed a higher propensity to form hydrogen bonds with phospholipid head groups.Notably,ssRNA exhibited stronger binding energy than ssDNA.Furthermore,divalent ions,particularly Ca2+,facilitated the binding of ssRNA to phospholipids due to their higher binding energy and lower dissociation rate from phospholipids.Overall,our study provides valuable insights into the molecular mechanisms underlying nucleic acidphospholipid interactions,with potential implications for the nucleic acids in biotherapies,particularly in the context of lipid carriers.展开更多
Rare earth doped silica films were prepared by sol-gel method accompanied with the spin-coating process. It was found that the photoluminescence (PL) property of the thin films was dependent strongly on the doping amo...Rare earth doped silica films were prepared by sol-gel method accompanied with the spin-coating process. It was found that the photoluminescence (PL) property of the thin films was dependent strongly on the doping amount of Eu3+. For thin films annealed at 700 ℃, the PL intensity increased constantly as elevating the doping amount up to 10% without any evident concentration quench, which indicated the good doping property of the SiO_2 matrix. In order to further improve the PL efficiency, co-doping of Tb3+ into SiO_2∶Eu3+ thin films were also investigated. It was found that the luminescence intensity was obviously enhanced by co-doping which could be explained in terms of the effective energy transfer from Tb3+ to Eu3+.展开更多
基金Project supported by the National Key Research and Development Program of China (Grant No.2021YFA1400400)the National Natural Science Foundation of China (Grant Nos.92165205,12074175,and 12374137)。
文摘By utilizing the fluctuation exchange approximation method,we perform a study on the superconducting pairing symmetry in a t_(2g) three-orbital model on the square lattice.Although the tight-binding parameters of the model are based on Sr_(2)RuO_(4),we have systematically studied the evolution of superconducting pairing symmetry with the carrier density and interactions,making our findings relevant to a broader range of material systems.Under a moderate Hund’s coupling,we find that spin fluctuations dominate the superconducting pairing,leading to a prevalent spin-singlet pairing with a d_(x^(2)-y^(2))-wave symmetry for the carrier density within the range of n=1.5-4 per site.By reducing the Hund’s coupling,the charge fluctuations are enhanced and play a crucial role in determining the pairing symmetry,leading to a transition of the pairing symmetry from the spin-singlet d_(x^(2)-y^(2))-wave to the spin-triplet p-wave.Furthermore,we find that the superconducting pairings are orbital dependent.As the carrier density changes from n=4 to n=1.5,the active orbitals for superconducting pairing shift from the quasi-two-dimensional orbital dxy to the quasi-one-dimensional orbitals d_(xz) and d_(yz).
基金Project supported by the National Key R&D Program of China(Grant Nos.2021YFB3502400 and 2022YFA1403601)the National Natural Science Foundation of China(Grant Nos.12274204,12274203,51831005,52172270,11974165,92165103,51971110,12004329,and 12241402).
文摘Recent theory and experiments show that artificial magnetic skyrmions can be stabilized at room temperature without the need for the external magnetic field,casting strong potentials for the device applications.In this work,we study the electric field manipulation of artificial magnetic skyrmions imprinted by Co disks on CoPt multilayers utilizing the micromagnetic simulations.We find that the reversible annihilation and creation of skyrmions can be realized with the electric field via the strain mediated magnetoelastic coupling.In addition,we also demonstrate controllable manipulation of individual skyrmion,which opens a new platform for constructing magnetic field-free and low-energy dissipation skyrmion based media.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1403201)the National Natural Science Foundation of China(Grant Nos.12204231,12061131001,52072170,and 11927809)the Strategic Priority Research Program(B)of Chinese Academy of Sciences(Grant No.XDB25000000).
文摘The discovery of high-temperature superconductivity near 80K in bilayer nickelate La_(3)Ni_(2)O_(7)under high pressures has renewed the exploration of superconducting nickelate in bulk materials.The extension of superconductivity in other nickelates in a broader family is also essential.Here,we report the experimental observation of superconducting signature in trilayer nickelate La_(4)Ni_(3)O_(10)under high pressures.By using a modified solgel method and post-annealing treatment under high oxygen pressure,we successfully obtained polycrystalline La_(4)Ni_(3)O_(10)samples with different transport behaviors at ambient pressure.Then we performed high-pressure electrical resistance measurements on these samples in a diamond-anvil-cell apparatus.Surprisingly,the signature of possible superconducting transition with a maximum transition temperature(T_(c))of about 20K under high pressures is observed,as evidenced by a clear drop of resistance and the suppression of resistance drops under magnetic fields.Although the resistance drop is sample-dependent and relatively small,it appears in all of our measured samples.We argue that the observed superconducting signal is most likely to originate from the main phase of La_(4)Ni_(3)O_(10).Our findings will motivate the exploration of superconductivity in a broader family of nickelates and shed light on the understanding of the underlying mechanisms of high-T_(c) superconductivity in nickelates.
基金supported by the National Natural Science Foundation of China(Grant Nos.11927809,13001241,and E0209/52072170)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB25000000)。
文摘We successfully grow a new superconductor GaBa2Ca3Cu4O11+δ(Ga-1234) with a transition temperature of 113 K, using the Walker-type high-pressure synthesis apparatus. X-ray diffraction measurements on the powderized samples show a mixture of the Ga-1234 phase and the Ca0.85CuO2phase, and the former is dominant. Under the scanning electron microscope, plate-like crystals of the Ga-based 1234 phase with shiny surfaces can be seen.The obtained local chemical compositions revealed by energy dispersion x-ray spectroscopy are very close to the stoichiometric values. On some sub-millimeter crystal-like samples of the 1234 phase, we obtain a full Meissner shielding volume. From the temperature-dependent magnetizations, we determine the irreversibility fields and find that the system exhibits a highly anisotropic behavior.
基金supported by the National Key R&D Program of China (Grant Nos.2022YFA1403602 and 2021YFB3601600)the National Natural Science Foundation of China (Grant Nos.51971109,U22A20117,51771053,52001169,11874199,12104216,and 12241403)the Natural Science Foundation of Jiangsu Province of China (Grant No.BK20200307)。
文摘We investigate the structural,static magnetic and damping properties in two Mn-deficient magnetic Weyl semimetal Co-Mn-Ga(CMG) alloy films,i.e.,Co_(55)Mn_(18)Ga_(27)(CMG1) and Co_(50)Mn_(18)Ga_(32)(CMG2),which were epitaxially grown on MgO(001) substrates.CMG1 has a mixing phase of B2and L21,larger saturation magnetization(M_(s) ~760 emu/cm^(3)),stronger in-plane magnetic anisotropy.CMG2 has an almost pure B2phase,smaller M_(s)(~330 emu/cm^(3)),negligible in-plane magnetic anisotropy.Time-resolved magneto-optical Kerr effect results unambiguously demonstrate an obvious perpendicular standing spin wave(PSSW) mode in addition to the Kittel mode for both of the CMG films.The intrinsic damping constant is about 0.0055 and 0.015 for CMG1 and CMG2,respectively,which are both significantly larger than that of the stoichiometric CMG(i.e.,Co_(2)MnGa)film reported previously.In combination with the first-principles calculations,the intrinsic damping properties of the Mn-deficient CMG films can be well explained by considering the increase of density of states at the Fermi level,reduction of M_(s),and excitation of the PSSW mode.These findings provide a new clue to tuning the magnetic damping of the magnetic Weyl semimetal film through slight off-stoichiometry.
基金supported by the National Natural Science Foundation of China (Grant No. 10574063)
文摘This paper studies the normal state properties of itinerant electrons in a toy model,which is constructed according to the model for coexisting ferromagnetism and superconductivity proposed by Suhl [Suhl H 2001 Phys.Rev.Lett.87 167007].In this theory with ferromagnetic ordering based on localized spins,the exchange interaction J between conduction electrons and localized spin is taken as the pairing glue for s-wave superconductivity.It shows that this J term will first renormalize the normal state single conduction electron structures substantially.It finds dramatically enhanced or suppressed magnetization of itinerant electrons for positive or negative J.Singlet Cooper pairing can be ruled out due to strong spin polarisation in the J > 0 case while a narrow window for s-wave superconductivity is opened around some ferromagnetic J.
基金Supported by the National Natural Science Foundation of China under Grant No 90503012, and the National Basic Research Programme of China under Grant Nos 2004CB619004 and 2006CB921803.
基金Supported by the National Natural Science Foundation of China under Grant No 10674059, the National High Technology Research and Development Program of China under Grant No 2007AA021805, and the National Basic Research Program of China under Grant No 2005CB623605.
基金Project supported by the National Key Research and Development Program of China (Grant No. 2022YFA1403602)the National Natural Science Foundation of China (Grant Nos. 51971109, 52025012, and 52001169)。
文摘Electric-field control of perpendicular magnetic anisotropy(PMA) is a feasible way to manipulate perpendicular magnetization,which is of great importance for realizing energy-efficient spintronics.Here,we propose a novel approach to accomplish this task at room temperature by resistive switching(RS) via electrochemical metallization(ECM) in a device with the stack of Si/SiO_(2)/Ta/Pt/Ag/Mn-doped ZnO(MZO)/Pt/Co/Pt/ITO.By applying certain voltages,the device could be set at high-resistance-state(HRS) and low-resistance-state(LRS),accompanied with a larger and a smaller coercivity(H_(C)),respectively,which demonstrates a nonvolatile E-field control of PMA.Based on our previous studies and the present control experiments,the electric modulation of PMA can be briefly explained as follows.At LRS,the Ag conductive filaments form and pass through the entire MZO layer and finally reach the Pt/Co/Pt sandwich,leading to weakening of PMA and reduction of H_(C).In contrast,at HRS,most of the Ag filaments dissolve and leave away from the Pt/Co/Pt sandwich,causing partial recovery of PMA and an increase of H_(C).This work provides a new clue to designing low-power spintronic devices based on PMA films.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.21264016,11464047,and 21364016)the National Basic Research Program of China(Grant No.2012CB821500)the Natural Science Foundation of Xinjiang Uygur Autonomous Region,China(Grant No.2013211A053)
文摘In this paper, we use a molecular theory to study the anomalous switching of ss DNA monolayers. Here, both ss DNA–water and water–water hydrogen bonds and their explicit coupling to the ss DNA conformations are considered. We find that hydrogen bonding becomes a key element in inducing the anomalous switching of ss DNA monolayers. This finding accords well with the experimental observations. Based on our theoretical model, we predict that the anomalous switching induced by water vapor will be applicable to a wide range of hydrogen bonds polymers, and ss DNA–water hydrogen bonds and water–water hydrogen bonds hybridization will lead to the hydrogen-bond network formation of 3D ss DNA monolayers.
基金supported by the National Key Projects for Research and Development of China(Grant No.2021YFA1400400)the National Natural Science Foundation of China(Grant Nos.12004191,92165205,12074175)+1 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20200738)the Natural Science Research Start-up Foundation of Posts and Telecommunications(Grant No.NY220095)。
文摘We study the motion of a hole with internal degrees of freedom,introduced to the zigzag magnetic ground state of Na_(2)IrO_(3),by using the self-consistent Born approximation.We find that the low-,intermediate-,and high-energy spectra are primarily attributed to the singlet,triplet,and quintet hole contributions,respectively.The spectral functions exhibit distinct features such as the electron-like dispersion of low-energy states near the L point,the maximum M-point intensity of mid-energy states,and the hole-like dispersion of high-energy states.These features are robust and almost insensitive to the exchange model and Hund's coupling,and are in qualitative agreement with the angular-resolved photoemission spectra observed in Na_(2)IrO_(3).Our results reveal that the interference between internal degrees of freedom in different sublattices plays an important role in inducing the complex dispersions.
基金Project supported by the Joint Funds of Xinjiang Natural Science Foundation,China(Grant No.2015211C298)
文摘Using a molecular theory, we investigate the temperature-dependent self-assembly of single-stranded DNA(ss DNA)tethered to a charged nanoparticle surface. Here the size, conformations, and charge properties of ss DNA are taken into account. The main results are as follows: i) when the temperature is lower than the critical switching temperature, the ss DNA will collapse due to the existence of electrostatic interaction between ss DNA and charged nanoparticle surface; ii)for the short ss DNA chains with the number of bases less than 10, the switching of ss DNA cannot happen, and the critical temperature does not exist; iii) when the temperature increases, the electrostatic attractive interaction between ss DNA and charged nanoparticle surface becomes weak dramatically, and ss DNA chains will stretch if the electrostatic attractive interaction is insufficient to overcome the elastic energy of ss DNA and the electrostatic repulsion energy. These findings accord well with the experimental observations. It is predicted that the switching of ss DNA will not happen if the grafting densities are too high.
基金Supported by the National Natural Science Foundation of China under Grant No 10804017, the Natural Science Foundation of Jiangsu Province under Grant No BK2007118, Research Fund for the Doctoral Program of Higher Education of China under Grant No 20070286037, Cyanine-Project Foundation of Jiangsu Province under Grant No 1107020060, Foundation for Climax Talents Plan in Six-Big Fields of Jiangsu Province under Grant No 1107020070, and New Century Excellent Talents in University （NCET-05-0452）.
文摘高质量的做 Ga 的 ZnO (ZnO : Ga ) 有各种各样的 Ga 集中的单个水晶的电影用分子横梁的取向附生在一飞机蓝宝石底层上被种。做的 Ga 原子的地点配置借助于 X 光吸收光谱学被学习。将近，所有 Ga 能作为电子上活跃的施主代替进 ZnO 格子，这被发现，有大约一个电子的自由搬运人的产生高密度每 Ga 掺杂物 Ga 集中是什么时候仅仅 2% 。然而，进一步增加做集中的 Ga 由于 Ga 原子的部分分离导致传导性的减少到尖晶石 ZnGa2O4 的次要的阶段或另外的中间的阶段。看起来在 ZnO 单个水晶的电影的 Ga 的最大的溶解度是大约 2 at.% ，最低抵抗力能到达 1.92 ? 潣楮 ? 潲杵湨獥 ? 楤浡瑥牥栯楥桧 ? 湡 ? 灄映牯猠牵慦散瀠潲楦敬 ? 慭楸畭 ? 潲杵湨獥 ? 慢敳搠慩敭整 ? 慭? 琠敨爠瑡潩 ? 景挠湯捩爠畯桧敮獳栠楥桧 ? 潴椠獴戠獡 ? 慲楤獵愠 ? 敷汬愠 ? 桴 ? 慲楴? 業浮硡漠 ? 桴 ? 業楮畭 ? 潴琠敨洠硡浩污戠獡 ? 楤浡瑥牥？
基金Supported by the National Natural Science Foundation of China under Grant No 60877029, the Natural Science Foundation of Tianjin under Grant Nos 06TXTJJC14600, 07JCYBJC06400 and 06YFJZJC00100, and Tianjin Key Subject for Materials Physics and Chemistry.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFA0300803)the National Natural Science Foundation of China(Grant Nos.51971109,51771053,and 51471085)Scientific Research Foundation of Nanjing Institute of Technology(Grant Nos.ZKJ201708 and CKJB201708).
文摘Tuning magnetic damping constant in dedicated spintronic devices has important scientific and technological implications. Here we report on anisotropic damping in various compositional amorphous CoFeB films grown on GaAs(001) substrates. Measured by a vector network analyzer-ferromagnetic resonance (VNA-FMR) equipment, a giant magnetic damping anisotropy of 385%, i.e., the damping constant increases by about four times, is observed in a 10-nm-thick Co40Fe40B20 film when its magnetization rotates from easy axis to hard axis, accompanied by a large and pure in-plane uniaxial magnetic anisotropy (UMA) with its anisotropic field of about 450 Oe. The distinct damping anisotropy is mainly resulted from anisotropic two-magnon-scattering induced by the interface between the ferromagnetic layer and the substrate, which also generates a significant UMA in the film plane.
基金Supported by the National Natural Science Foundation of China under Grant No 61176124the National Basic Research Program of China under Grant No 2010CB934201the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘The charge-storage characteristics of charge trapping memory devices containing different sizes of Au nanocrystals(NCs)sandwiched by Al2O3 tunneling and blocking layers are studied.A strong impact of both Au NC size and inter-NC distance on the charge trapping capability of the devices is observed.The total surface area of Au NCs associated with Au NC size is supposed to be a key factor in the charge-storage capability,and the device with larger size of Au NCs and a suitable inter-NC distance will possess better charge trapping capability.Variable range hopping as the lateral charge loss mechanism is considered as the main reason for the decrease of the charge trapping capability when Au NCs grow and overlap neighbors.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12222506,12347102,and 12174184).
文摘Recently,lipid nanoparticles(LNPs)have been extensively investigated as non-viral carriers of nucleic acid vaccines due to their high transport efficiency,safety,and straightforward production and scalability.However,the molecular mechanism underlying the interactions between nucleic acids and phospholipid bilayers within LNPs remains elusive.In this study,we employed the all-atom molecular dynamics simulation to investigate the interactions between single-stranded nucleic acids and a phospholipid bilayer.Our findings revealed that hydrophilic bases,specifically G in single-stranded RNA(ssRNA)and single-stranded DNA(ssDNA),displayed a higher propensity to form hydrogen bonds with phospholipid head groups.Notably,ssRNA exhibited stronger binding energy than ssDNA.Furthermore,divalent ions,particularly Ca2+,facilitated the binding of ssRNA to phospholipids due to their higher binding energy and lower dissociation rate from phospholipids.Overall,our study provides valuable insights into the molecular mechanisms underlying nucleic acidphospholipid interactions,with potential implications for the nucleic acids in biotherapies,particularly in the context of lipid carriers.
基金Supported by National Basic Research Program of China under Grant No 2007CB925104, and the National Natural Science Foundation of China under Grant No 10874076.
文摘训练效果和交换偏爱的尖依赖的磁滞现象行为广泛地在 IrMn 层厚度 t <SUB 的变化之上被调查 > 在一系列 Co/IrMn 双性人层的 IrMn </SUB> 。什么时候 t <SUB > IrMn </SUB> 是很小的，他们俩是可以忽略的。然后，他们与增加 t <SUB 很严厉地增加 > IrMn </SUB> 然后活动范围最大值在几乎 t <SUB 的一样的价值 > IrMn </SUB> 。当时，最后，他们两个都减少 t <SUB > IrMn </SUB> 进一步被增加。类似的变化趋势建议这些现象从反铁磁性物质旋转取向的不可逆的变化产生，根据热激活模型的意见。
基金Supported by the National Basic Research Program of China under Grant Nos 2006CB921803, 2009CB929504 and 2010CB923401, and the National Natural Science Foundation of China under Grant Nos 60825402 and 60421003.
基金the NSF of China (60425414 ,10574069)State Key Program for Basic Research (2007CB613401)
文摘Rare earth doped silica films were prepared by sol-gel method accompanied with the spin-coating process. It was found that the photoluminescence (PL) property of the thin films was dependent strongly on the doping amount of Eu3+. For thin films annealed at 700 ℃, the PL intensity increased constantly as elevating the doping amount up to 10% without any evident concentration quench, which indicated the good doping property of the SiO_2 matrix. In order to further improve the PL efficiency, co-doping of Tb3+ into SiO_2∶Eu3+ thin films were also investigated. It was found that the luminescence intensity was obviously enhanced by co-doping which could be explained in terms of the effective energy transfer from Tb3+ to Eu3+.
