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Indelible Rules of Josephson Coupling Energy and Zero-Point Energy in High-Tc Cuprates
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作者 LIUFu-Sui CHENWan-Fang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第4期629-631,共3页
This paper shows that the Josephson coupling energy and the zero-point energy have indelible rules on the superfluid density and the superconductivity in the high-T<SUB>c</SUB> cuprates. This paper also sh... This paper shows that the Josephson coupling energy and the zero-point energy have indelible rules on the superfluid density and the superconductivity in the high-T<SUB>c</SUB> cuprates. This paper also shows that the values of T<SUB>c</SUB> at underdoped and overdoped regions are determined by the damage conditions of the phase coherence in the classical and the quantum XY-models, respectively. 展开更多
关键词 HIGH-T-C cuprates superfluid density Josephson coupling zero-point energy
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A NEW APPROACH TO THE SYNTHESES OF THE PHEROMONES OF JAPANESE BEETLE AND BONTEBOK WITH(Z)-VINYL CUPRATES
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作者 Zhang Huang XU YI Jun PAN +1 位作者 Jian Hong ZHAO Yan LI 《Chinese Chemical Letters》 SCIE CAS CSCD 1993年第5期395-398,共4页
The dl-form of the sex pheromone of Japanese b(?)tle and the trail pheromone of Bontebok were synthesised in high purity of (Z)-olefinic configuration. The key step of the syntheses of compounds (1) and (2) involved s... The dl-form of the sex pheromone of Japanese b(?)tle and the trail pheromone of Bontebok were synthesised in high purity of (Z)-olefinic configuration. The key step of the syntheses of compounds (1) and (2) involved stereospecific addition of n-alkyl cuprates to acetylene followed by addition of vinyl cuprates to aldehyde (7) and 3-buten--2-one. 展开更多
关键词 HMPA A NEW APPROACH TO THE SYNTHESES OF THE PHEROMONES OF JAPANESE BEETLE AND BONTEBOK WITH VINYL cuprates
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Hybrid crystals of cuprates and iron-based superconductors
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作者 代霞 勒聪聪 +1 位作者 吴贤新 胡江平 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第7期412-418,共7页
We propose two possible new compounds, Ba2CuO2Fe2As2and K2CuO2Fe2Se2, which hybridize the building blocks of two high temperature superconductors, cuprates and iron-based superconductors. These compounds consist of sq... We propose two possible new compounds, Ba2CuO2Fe2As2and K2CuO2Fe2Se2, which hybridize the building blocks of two high temperature superconductors, cuprates and iron-based superconductors. These compounds consist of square CuO2 layers and antifluorite-type Fe2X2(X = As, Se) layers separated by Ba/K. The calculations of binding energies and phonon spectra indicate that they are dynamically stable, which ensures that they may be experimentally synthesized. The Fermi surfaces and electronic structures of the two compounds inherit the characteristics of both cuprates and iron-based superconductors. These compounds can be superconductors with intriguing physical properties to help to determine the pairing mechanisms of high Tc superconductivity. 展开更多
关键词 iron-based superconductors cuprates first-principle calculation
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Crystal Growth of Cu6(Ge,Si)6O18&#183;6H2O and Assignment of UV-VIS Spectra in Comparison to Dehydrated Dioptase and Selected Cu(II) Oxo-Compounds Including Cuprates
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作者 Hans Hermann Otto 《World Journal of Condensed Matter Physics》 2017年第3期57-79,共23页
Low-dimensional quantum spin systems with the Cu2+ central ion are still in the focus of experimental and theoretical research. Here is reported on growth of mm-sized single-crystals of the low-dimensional S = 1/2 spi... Low-dimensional quantum spin systems with the Cu2+ central ion are still in the focus of experimental and theoretical research. Here is reported on growth of mm-sized single-crystals of the low-dimensional S = 1/2 spin compound Cu6(Ge,Si)6O18&#183;6H2O by a diffusion technique in aqueous solution. A route to form Si-rich crystals down to possible dioptase, the pure silicate, is discussed. Motivated by previously reported incorrect assignments of UV-VIS spectra, the assignment of dd excitations from such spectra of the hexahydrate and the fully dehydrated compound is proposed in comparison to dioptase and selected Cu(II) oxo-compounds using bond strength considerations. Non-doped cuprates as layer compounds show higher excitation energies than the title compound. However, when the antiferromagnetic interaction energy as Jz&#183;ln(2) is taken into account for cuprates, a single linear relationship between the Dqe excitation energy and equatorial Cu(II)-O bond strength is confirmed for all compounds. A linear representation is also confirmed between 2A1g energies and a function of axial and equatorial Cu-O bond distances if auxiliary axial bonds are used for four-coordinated compounds. The quotient Dt/Ds of experimental orbital energies deviating from the general trend to smaller values indicates the existence of H2O respectively Cl&minus;axial ligands in comparison to oxo-ligands, whereas larger Dt/Dqe values indicate missing axial bonds. The quotient of the excitation energy 2A1g by 2&#183;2Eg-2B2g allows checking for correctness of the assignment and to distinguish between axial oxo-ligands and others like H2O or Cl&minus;. 展开更多
关键词 Dioptase Ge-Dioptase Copper(II) COMPOUNDS cuprates Crystal Growth UV-VIS Spectroscopy EPR Color d-d Excitations Bond Strength Super-Exchange Interaction
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Oxygen Isotope Effects on T_(c) Related to Polaronic Superconductivity in Underdoped Cuprates
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作者 B.I.Kochelaev K.A.Müller A.Shengelaya 《Journal of Modern Physics》 2014年第6期473-476,共4页
The planar oxygen isotope effect on Tc observed in copper oxide superconductors is remarkable in that it increases from near nil at optimal doping to a value twice that derived from BCS theory in the underdoped region... The planar oxygen isotope effect on Tc observed in copper oxide superconductors is remarkable in that it increases from near nil at optimal doping to a value twice that derived from BCS theory in the underdoped region. This behavior is quantitatively followed by a formula proposed by Kresin and Wolf in 1994 for polarons along the c-axis. Herein it is revisited in a more transparent way, and it is pointed out that the heterogeneity of pairing is relevant and has to be taken into account to explain the unusual planar isotope effects on Tc in underdoped cuprates. 展开更多
关键词 cuprates High-Temperature Superconductivity POLARONS Isotope Effect
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Theoretical understanding of correlation between magnetic phase transition and the superconducting dome in high-Tc cuprates
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作者 Chen Zhang Cai-Xin Zhang +2 位作者 Su-Huai Wei Haiqing Lin Hui-Xiong Deng 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2024年第2期167-173,共7页
Many issues concerning the origin of high-temperature superconductivity(HTS)are still under debate.For example,how the magnetic order varies with doping and its relationship with the superconducting temperature(Tc);an... Many issues concerning the origin of high-temperature superconductivity(HTS)are still under debate.For example,how the magnetic order varies with doping and its relationship with the superconducting temperature(Tc);and why Tcalways peaks near the quantum critical point.In this paper,taking hole-doped La_(2)CuO_(4)as a classical example,we employ the first-principles band structure and total energy calculations with Monte Carlo simulations to explore how the symmetry-breaking magnetic ground state evolves with hole doping and the origin of a dome-shaped superconductivity region in the phase diagram.We demonstrate that the local antiferromagnetic order and doping play key roles in determining the electron-phonon coupling,thus Tc.Initially,the La_(2)CuO_(4)possesses a checkerboard local antiferromagnetic ground state.As the hole doping increases,Tcincreases with the enhanced electron-phonon coupling strength.But as the doping increases further,the strength of the antiferromagnetic interaction weakens and spin fluctuation increases.At the critical doping level,a magnetic phase transition occurs that reduces the local antiferromagnetism-assisted electron-phonon coupling,thus diminishing the Tc.The superconductivity disappears in the heavily overdoped region when the ferromagnetic order dominates.These observations could account for why cuprates have a dome-shaped superconductivity region in the phase diagram.Our study,thus,contributes to a fundamental understanding of the correlation between doping,local magnetic order,and superconductivity of HTS. 展开更多
关键词 high-temperature superconductivity antiferromagnetic order electron-phonon coupling doping effect cuprates
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Yttrium cuprates modification in linear generator application for power generation
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作者 Moses Eterigho Emetere 《Clean Energy》 EI CSCD 2024年第5期229-240,共12页
Yttrium barium copper oxide(YBCO)is used for special applications in linear generators because of its excitation loss,lower weight,and higher efficiency.These qualities enable the compound to operate better than the c... Yttrium barium copper oxide(YBCO)is used for special applications in linear generators because of its excitation loss,lower weight,and higher efficiency.These qualities enable the compound to operate better than the conventional copper wire coil in the stator unit of the linear generator.However,the continuous use of YBCO in linear generators has a fundamental challenge that affects industrial production and material stability after prolonged use.This paper seeks to sustain the adoption of YBCO by improving its quality for linear generator applications.The yttrium cuprates modification(YBYbCO)was synthesized using the solid-state reaction technique by doping YBCO with ytterbium.The crystalline structure,microstructural pattern,and stability of the new sample were adequately measured and found to be structurally stable to ensure durability.It was reported that applyingYBYbCO in the linear generator would lead to a 200%increase in energy generation.The higher number of particles and lower individual particulate resistance enable it to withstand chemical pressure,thereby prolonging the lifespan of the linear generator. 展开更多
关键词 MICROSTRUCTURE YBCO structure linear generator cuprates clean energy SDG7
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Relationship between the parent charge transfer gap and maximum transition temperature in cuprates 被引量:3
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作者 Wei Ruan Cheng Hu +10 位作者 Jianfa Zhao Peng Cai Yingying Peng Cun Ye Runze Yu Xintong Li Zhenqi Hao Changqing Jin Xingjiang Zhou Zheng-Yu Weng Yayu Wang 《Science Bulletin》 SCIE EI CAS CSCD 2016年第23期1826-1832,共7页
One of the biggest puzzles concerning the cup- rate high temperature superconductors is what determines the maximum transition temperature (Tc,max), which varies from less than 30 to above 130 K in different compoun... One of the biggest puzzles concerning the cup- rate high temperature superconductors is what determines the maximum transition temperature (Tc,max), which varies from less than 30 to above 130 K in different compounds. Despite this dramatic variation, a robust trend is that within each family, the double-layer compound always has higher Tc,max than the single-layer counterpart. Here we use scanning tunneling microscopy to investigate the electronic structure of four cuprate parent compounds belonging to two different families. We find that within each family, the double layer compound has a much smaller charge transfer gap size (ACT), indicating a clear anticorrelation between AcT and Tc,max. These results suggest that the charge transfer gap plays a key role in the superconducting physics of cuprates, which shed important new light on the high To mechanism from doped Mott insulator perspective. 展开更多
关键词 cuprates Mot insulator Charge transfer gap - Maximum transition temperature Scanning tunneling microscopy
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Structural and superconducting properties in Y_(0.6)Gd_(0.4)Ba_2(Nb)Cu_3O_(7-y) cuprates doped with niobium 被引量:2
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作者 M. Yilmaz O. Dogan 《Journal of Rare Earths》 SCIE EI CAS CSCD 2012年第3期241-244,共4页
Polycrystalline YBa2Cu3O7-y (YBCO) and Y0.6Gd0.4Ba2-xNbxCu3O7-y (YGBNCO) compounds with 0≤x≤0.225 were synthesized using standard solid state reaction technique. The structure for all samples was characterized b... Polycrystalline YBa2Cu3O7-y (YBCO) and Y0.6Gd0.4Ba2-xNbxCu3O7-y (YGBNCO) compounds with 0≤x≤0.225 were synthesized using standard solid state reaction technique. The structure for all samples was characterized by X-ray difference (XRD) and scanning electron microscopy (SEM). The transport properties were measured by the (FPP) method in the temperature range from 70 to 130 K. As the Nb content in the samples increased, a diffused phase indicating a niobium perovskite phase and a small amount of unidentified phase appeared. With the increase of Nb content, the superconducting transition temperature Tconset increased slowly with x≤0.125, and then it remained unchanged or slowly decreased with 0.125≤x≤0.225. It could be found that there was a slow decrease of zero-resistance temperature, Tcoffset, with the increase of Nb content. The larger transition width might result from the YBa2NbO6 phase, impurity and unidentified phases of the sample due to the Nb doping. 展开更多
关键词 Y0.6Gd0.4Ba2Cu3O7-y cuprates Gd and Nb co-doping structural and superconducting properties rare earths
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Negligible normal fluid in superconducting state of heavily overdoped Bi_(2)Sr_(2)CaCu_(2)O_(8+δ) detected by ultra-low temperature angle-resolved photoemission spectroscopy
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作者 殷超辉 汪清泓 +23 位作者 解于洋 陈逸雯 刘俊豪 杨鉴刚 贾俊杰 张杏 吕文凯 闫宏涛 戎洪涛 张申金 王志敏 宗楠 刘丽娟 李如康 王晓洋 张丰丰 杨峰 彭钦军 许祖彦 刘国东 毛寒青 赵林 李昕彤 周兴江 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第7期562-567,共6页
In high temperature cuprate superconductors,it was found that the superfluid density decreases with the increase of hole doping.One natural question is whether there exists normal fluid in the superconducting state in... In high temperature cuprate superconductors,it was found that the superfluid density decreases with the increase of hole doping.One natural question is whether there exists normal fluid in the superconducting state in the overdoped region.In this paper,we have carried out high-resolution ultra-low temperature laser-based angle-resolved photoemission measurements on a heavily overdoped Bi2212 sample with a T_(c) of 48 K.We find that this heavily overdoped Bi2212 remains in the strong coupling regime with 2Δ_(0)/(k_(B)T_(c))=5.8.The single-particle scattering rate is very small along the nodal direction(~5 meV) and increases as the momentum moves from the nodal to the antinodal regions.A hard superconducting gap opening is observed near the antinodal region with the spectral weight at the Fermi level fully suppressed to zero.The normal fluid is found to be negligibly small in the superconducting state of this heavily overdoped Bi2212.These results provide key information to understand the high T_(c) mechanism in the cuprate superconductors. 展开更多
关键词 cuprate superconductor angle-resolved photoemission spectroscopy electronic structure
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Extraction of tight binding parameters from in-situ ARPES on the continuously doped surface of cuprates
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作者 YiGui Zhong YiMeng Chen +6 位作者 JianYu Guan Jin Zhao ZhiCheng Rao CenYao Tang HaiJiang Liu YuJie Sun Hong Ding 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2018年第12期25-29,共5页
Recently we developed a technique of ozone/vacuum annealing to continuously change the doping level of the surface of Bi_2Sr_2CaCu_2O_(8+)and measured a nearly whole superconducting dome on one surface by in-situ angl... Recently we developed a technique of ozone/vacuum annealing to continuously change the doping level of the surface of Bi_2Sr_2CaCu_2O_(8+)and measured a nearly whole superconducting dome on one surface by in-situ angle-resolved photoemission spectroscopy [arXiv: 1805.06450]. Here we study the evolution of the electronic structures of Bi_2Sr_2CaCu_2O_(8+)xusing this technique together with tight binding fits. The tight binding parameters are extracted to study their evolution with doping. 展开更多
关键词 cuprates electronic structures DOPING evolution TIGHT BINDING ARPES
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Monolayer NbF:a 4d-analogue of cuprates
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作者 Yang Yang Wan-Sheng Wang +1 位作者 Chin-Sen Ting Qiang-Hua Wang 《Science Bulletin》 SCIE EI CAS CSCD 2020年第22期1901-1906,M0004,共7页
The electronic structure and possible electronic orders in monolayer NbF4 are investigated by density functional theory and functional renormalization group.Because of the niobium-centered octahedra,the energy band ne... The electronic structure and possible electronic orders in monolayer NbF4 are investigated by density functional theory and functional renormalization group.Because of the niobium-centered octahedra,the energy band near the Fermi level is found to derive from the 4 dxyorbital,well separated from the other bands.Local Coulomb interaction drives the undoped system into an antiferromagnetic insulator.Upon suitable electron/hole doping,the system is found to develop dx2à-y2 wave superconductivity with sizable transition temperature.Therefore,the monolayer NbF4 may be an exciting 4d1 analogue of cuprates,providing a new two-dimensional platform for high-Tc superconductivity. 展开更多
关键词 cuprates Two-dimensional superconductors d-wave pairing Electronic structure calculations
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High-magnetic-field induced charge order in high-T_c cuprate superconductors 被引量:2
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作者 L X Zheng J Li T WU 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第11期25-42,共18页
In the last few years, charge order and its entanglement with superconductivity are under hot debate in high-Tc community due to the new progress on charge order in high-Tc cuprate superconductors YBa2Cu3O6+x. Here, w... In the last few years, charge order and its entanglement with superconductivity are under hot debate in high-Tc community due to the new progress on charge order in high-Tc cuprate superconductors YBa2Cu3O6+x. Here, we will briefly introduce the experimental status of this field and mainly focus on the experimental progress of high-field nuclear magnetic resonance(NMR) study on charge order in YBa2Cu3O6+x. The pioneering high-field NMR work in YBa2Cu3O6+x sets a new stage for studying charge order which has become a ubiquitous phenomenon in high-Tc cuprate superconductors. 展开更多
关键词 CHARGE order cuprates NUCLEAR magnetic RESONANCE YBa2Cu3O6+x SUPERCONDUCTORS competing order
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A Different Approach to High-Tc Superconductivity: Indication of Filamentary-Chaotic Conductance and Possible Routes to Room Temperature Superconductivity 被引量:9
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作者 Hans Hermann Otto 《World Journal of Condensed Matter Physics》 CAS 2016年第3期244-260,共18页
The empirical relation of between the transition temperature of optimum doped superconductors T<sub>co</sub> and the mean cationic charge , a physical paradox, can be recast to strongly support fractal the... The empirical relation of between the transition temperature of optimum doped superconductors T<sub>co</sub> and the mean cationic charge , a physical paradox, can be recast to strongly support fractal theories of high-T<sub>c</sub> superconductors, thereby applying the finding that the optimum hole concentration of σ<sub>o</sub> = 0.229 can be linked with the universal fractal constant δ<sub>1</sub> = 8.72109… of the renormalized quadratic Hénon map. The transition temperature obviously increases steeply with a domain structure of ever narrower size, characterized by Fibonacci numbers. However, also conventional BCS superconductors can be scaled with δ<sub>1</sub>, exemplified through the energy gap relation k<sub>B</sub>T<sub>c</sub> ≈ 5Δ<sub>0</sub>/δ<sub>1</sub>, suggesting a revision of the entire theory of superconductivity. A low mean cationic charge allows the development of a frustrated nano-sized fractal structure of possibly ferroelastic nature delivering nano-channels for very fast charge transport, in common for both high-T<sub>c</sub> superconductor and organic-inorganic halide perovskite solar materials. With this backing superconductivity above room temperature can be conceived for synthetic sandwich structures of less than 2+. For instance, composites of tenorite and cuprite respectively tenorite and CuI (CuBr, CuCl) onto AuCu alloys are proposed. This specification is suggested by previously described filamentary superconductivity of “bulk” CuO1﹣x samples. In addition, cesium substitution in the Tl-1223 compound is an option. 展开更多
关键词 SUPERCONDUCTIVITY Fractals Chaos Feigenbaum Numbers Fibonacci Numbers Golden Mean Ferroelastic Domains Mean Cationic Charge Perovskites cuprates TENORITE CUPRITE Cesium Substitution Solar Power Conversion Efficiency
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Orbital Approach to High Temperature Superconductivity 被引量:1
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作者 Peter Love 《Natural Science》 2019年第1期1-7,共7页
High temperature superconductivity in cuprates is explained in terms of 3d-orbital capture in copper. In elemental Cu 3d-orbital capture abstracts an electron from the 4 s2 valence orbital, and leaves it as 4 s1. This... High temperature superconductivity in cuprates is explained in terms of 3d-orbital capture in copper. In elemental Cu 3d-orbital capture abstracts an electron from the 4 s2 valence orbital, and leaves it as 4 s1. This is known since Cu occurs in Group IB of the Periodic Table. This forms an electron vacancy, or hole, in the valence shell. Therefore, the energy of 3d-orbital capture is stronger than the energy of unpairing of a paired-spin 4 s2 orbital. In cuprates 3d-orbital capture abstracts an electron from a Cu-O covalent bond, and leaves a hole in the excited state orbital. By electron-hole migration the excited state orbital leads to a coordinate covalent bond. This leads to superconductivity. The 3d-orbital process accounts for superconductivity and insulator behavior in cuprates. These results lend credence to the statement that 3d-orbital capture in copper is the cause of high temperature superconductivity. 展开更多
关键词 High Temperature SUPERCONDUCTIVITY D-Orbital CAPTURE cuprates COORDINATE COVALENT Bonding
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Study of Pseudogap in Underdoped Cuprate
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作者 LOU Ping WU Hang-Sheng 《Communications in Theoretical Physics》 SCIE CAS CSCD 2001年第7期91-94,共4页
A mean-field spin-density wave (SDW) analysis of pseudogap in the underdoped cuprates is proposed on the dependence of the energy gap which mimics the pseudogap near (π, 0) point at least. It implies that the pseudog... A mean-field spin-density wave (SDW) analysis of pseudogap in the underdoped cuprates is proposed on the dependence of the energy gap which mimics the pseudogap near (π, 0) point at least. It implies that the pseudogap structure near (π, 0) is not sensitive to the long-range order and will survive leading to the pseudogap phenomenon in the underdoped metallic phase. On the other hand, in the long-range ordering antiferromagnetic region, the mean-field SDW theory holds and the pseudogap structure predicated by the theory should be observable experimentallyv. Then one prediction is that the pseudogap would smoothly extrapolate between itinerant antiferromagnetic phase and underdoped metallic phase. 展开更多
关键词 high-temperature superconductors pseudogap underdoped cuprates MEAN-FIELD SDW analysis
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Specific heat in superconductors
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作者 Hai-Hu Wen 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第1期24-39,共16页
Specific heat is a powerful tool to investigate the physical properties of condensed materials.Superconducting state is achieved through the condensation of paired electrons,namely,the Cooper pairs.The condensed Coope... Specific heat is a powerful tool to investigate the physical properties of condensed materials.Superconducting state is achieved through the condensation of paired electrons,namely,the Cooper pairs.The condensed Cooper pairs have lower entropy compared with that of electrons in normal metal,thus specific heat is very useful in detecting the low lying quasiparticle excitations of the superconducting condensate and the pairing symmetry of the superconducting gap.In this brief overview,we will give an introduction to the specific heat investigation of the physical properties of superconductors.We show the data obtained in cuprate and iron based superconductors to reveal the pairing symmetry of the order parameter. 展开更多
关键词 specific heat gap symmetry low lying quasiparticle excitations cuprates iron based superconductors
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An Overview of the Multi-Band and the Generalized BCS Equations-Based Approaches to Deal with Hetero-Structured Superconductors
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作者 G. P. Malik 《Open Journal of Microphysics》 2018年第2期7-13,共7页
We trace the conceptual basis of the Multi-Band Approach (MBA) and recall the reasons for its wide following for composite superconductors (SCs). Attention is then drawn to a feature that MBA ignores: the possibility ... We trace the conceptual basis of the Multi-Band Approach (MBA) and recall the reasons for its wide following for composite superconductors (SCs). Attention is then drawn to a feature that MBA ignores: the possibility that electrons in such an SC may also be bound via simultaneous exchanges of quanta with more than one ion-species—a lacuna which is addressed by the Generalized BCS Equations (GBCSEs). Based on several papers, we give a concise account of how this approach: 1) despite employing a single band, meets the criteria satisfied by MBA because a) GBCSEs are derived from a temperature-incorporated Bethe-Salpeter Equation the kernel of which is taken to be a “superpropagator” for a composite SC-each ion-species of which is distinguished by its own Debye temperature and interaction parameter and b) the band overlapping the Fermi surface is allowed to be of variable width. GBCSEs so-obtained reduce to the usual equations for the Tc and Δ of an elemental SC in the limit superpropagator → 1-phonon propagator;2) accommodates moving Cooper pairs and thereby extends the scope of the original BCS theory which restricts the Hamiltonian at the outset to terms that correspond to pairs having zero centre-of-mass momentum. One can now derive an equation for the critical current density (j0) of a composite SC at T = 0 in terms of the Debye temperatures of its ions and their interaction parameters— parameters that also determine its Tc and Δs;3) transforms the problem of optimizing j0 of a composite SC, and hence its Tc, into a problem of chemical engineering;4) provides a common canopy for most composite SCs, including those that are usually regarded as outside the purview of the BCS theory and have therefore been called “exceptional”, e.g., the heavy-fermion SCs;5) incorporates s±-wave superconductivity as an in-built feature and can therefore deal with the iron-based SCs, and 6) leads to presumably verifiable predictions for the values of some relevant parameters, e.g., the effective mass of electrons, for the SCs for which it has been employed. 展开更多
关键词 Hetero-Structured SUPERCONDUCTORS MULTI-BAND and Generalized BCS Equations-Based APPROACHES Unified Treatment of cuprates and Fe-Based SUPERCONDUCTORS Quest for Clues about Raising Tc
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Influence of the Pseudogap on the Inelastic Neutron Scattering Spectra of the Underdoped Lanthanum Cuprate 被引量:1
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作者 LOUPing CAOLie-Zhao 《Communications in Theoretical Physics》 SCIE CAS CSCD 2002年第4期499-502,共4页
The influence of pseudogap on the inelastic neutron scattering spectra of the underdoped lanthanum cuprate is studied on the basis of the model which incorporates both the superconducting state and pseudogap state. It... The influence of pseudogap on the inelastic neutron scattering spectra of the underdoped lanthanum cuprate is studied on the basis of the model which incorporates both the superconducting state and pseudogap state. It is found that the striking effects of the influence of the pseudogap on the incommensurability of the spin excitation spectrum are that in the superconducting state the pseudogap makes the intensity of the incommensurate peak increase, in the normal state the pseudogap not only makes the intensity of the incommensurate peak increase, but also sharpens the incommensurate peak and increases incommensurability. 展开更多
关键词 PSEUDOGAP neutron scattering spectra underdoped lanthanum cuprate
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Evidence for Multiple Underlying Fermi Surface and Isotropic Energy Gap in the Cuprate Parent Compound Ca2CuO2Cl2 被引量:1
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作者 Cheng Hu Jian-Fa Zhao +9 位作者 Ying Ding Jing Liu Qiang Gao Lin Zhao Guo-Oong Liu Li Yu Chang-Qing Jin Chuang-Tian Chen Zu-Yan Xu Xing-Jiang Zhou 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第6期84-89,共6页
The parent compounds of the high-temperature cuprate superconductors are Mott insulators.It has been generally agreed that understanding the physics of the doped Mott insulators is essential to understanding the mecha... The parent compounds of the high-temperature cuprate superconductors are Mott insulators.It has been generally agreed that understanding the physics of the doped Mott insulators is essential to understanding the mechanism of high temperature superconductivity.A natural starting point is to elucidate the basic electronic structure of the parent compound.Here we report comprehensive high resolution angle-resolved photoemission measurements on Ca_2CuO_2Cl_2,a Mott insulator and a prototypical parent compound of the cuprates.Multiple underl.ying Fermi surface sheets are revealed for the first time.The high energy waterfall-like band dispersions exhibit different behaviors near the nodal and antinodal regions.Two distinct energy scales are identified:a d-wave-like low energy peak dispersion and a nearly isotropic lower Hubbard band gap.These observations provide new information of the electronic structure of the cuprate parent compound,which is important for understanding the anomalous physical properties and superconductivity mechanism of the high temperature cuprate superconductors. 展开更多
关键词 CuO Evidence for Multiple Underlying Fermi Surface and Isotropic Energy Gap in the Cuprate Parent Compound Ca2CuO2Cl2 Ca Cl
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