Van der Waals (vdWs) stacking of two-dimensional (2D) materials can effectively weaken the Fermi level pinning (FLP) effect in metal/semiconductor contacts due to dangling-bond-free surfaces. However, the inherent vdW...Van der Waals (vdWs) stacking of two-dimensional (2D) materials can effectively weaken the Fermi level pinning (FLP) effect in metal/semiconductor contacts due to dangling-bond-free surfaces. However, the inherent vdWs gap always induces a considerable tunneling barrier, significantly limiting carrier injection. Herein, by inducing a sp^(2) to sp^(3) hybridization transformation in 2D carbon-based metal via surface defect engineering, the large orbital overlap can form an efficient carrier channel, overcoming the tunneling barrier. Specifically, by selecting the 2D carbon-based X_(3)C_(2) (X = Cd, Hg, and Zn) metal and the 2D MSi_(2)N_(4) (M = Cr, Hf, Mo, Ti, V, and Zr) semiconductor, we constructed 36 metal/semiconductor contacts. For vdWs contacts, although Ohmic contacts can be formed at the interface, the highest tunneling probability (P TB) is only 3.11%. As expected, the P TB can be significantly improved, as high as 48.73%, when MSi_(2)N_(4), accompanied by surface nitrogen vacancies, forms an interface covalent bond with X_(3)C_(2). Simultaneously, weak FLP and Ohmic contact remain at the covalent-bond-based surface, attributing to the protection of the MSi_(2)N_(4) band-edge electronic states by the outlying Si-N sublayer. Our work provides a promising path for advancing the progress of 2D electronic and photoelectronic devices.展开更多
In 2018, the CMS collaboration reported a di-photon excess at approximately 95.3 GeV with a local significance of 2.8 σ. Interestingly, the CMS collaboration also recently reported a di-tau excess at 95-100 GeV with ...In 2018, the CMS collaboration reported a di-photon excess at approximately 95.3 GeV with a local significance of 2.8 σ. Interestingly, the CMS collaboration also recently reported a di-tau excess at 95-100 GeV with a local significance of 2.6-3.1 σ. In addition, a bb excess at 98 GeV with a local significance of 2.3 σ was reported from LEP data approximately twenty years ago. In this study, we addressed the interpretation of these excesses together with a light Higgs boson in the next-to-minimal supersymmetric standard model(NMSSM). We conclude that, in the NMSSM, the 95-100 GeV excesses are difficult to be satisfied simultaneously(not possible globally at the 1σ level or simultaneously at the 2σ level). We analyzed two partially-satisfied scenarios: global 2σ and small di-photon. An approximate equation of global fit to the three excesses was derived, and two representative types of surviving samples were analyzed in detail. Given that the mass regions of these excesses are near the Z boson, we also checked the light Higgs boson in the tt-associated channels. The detailed results may be useful for further checking the low-mass-region excesses in the future.展开更多
Motivated by recent supersymmetry(SUSY)search results,which prefer most SUSY particles to be heavy,and the muon g–2 anomaly,which prefers colorless SUSY particles to be light,we explore the status of a light smuon(th...Motivated by recent supersymmetry(SUSY)search results,which prefer most SUSY particles to be heavy,and the muon g–2 anomaly,which prefers colorless SUSY particles to be light,we explore the status of a light smuon(the SUSY partner of a left-handed muon lepton)in the next-to-minimal supersymmetric standard model(NMSSM).Assuming colored SUSY particles to be heavy,and considering numerous experimental constraints,including muon g-2,SUSY searches,and dark matter,we scan the parameter space in the NMSSM with Z3-symmetry and check the status of colorless SUSY particles and their possible mass order,paying special attention to the smuon.After calculations and discussions,we find that the surviving samples can be divided into several scenarios,where the mass region and decay information of the smuon are given.Overall,the smuon mass can be approximately 0.1~1.8 TeV.These results may be useful for smuon searches at the LHC and future colliders.展开更多
基金supported by China Postdoctoral Science Foundation(No.2022M711691)the National Natural Science Foundation of China(Nos.12104130 and 12304085)+3 种基金Six talent peaks project in Jiangsu Province(No.XCL-104)the open research fund of Key Laboratory of Quantum Materials and Devices(Southeast University)Ministry of Education(No.3207022401C3)Natural Science Foundation of Nanjing University of Posts and Telecommunications(No.NY221102).
文摘Van der Waals (vdWs) stacking of two-dimensional (2D) materials can effectively weaken the Fermi level pinning (FLP) effect in metal/semiconductor contacts due to dangling-bond-free surfaces. However, the inherent vdWs gap always induces a considerable tunneling barrier, significantly limiting carrier injection. Herein, by inducing a sp^(2) to sp^(3) hybridization transformation in 2D carbon-based metal via surface defect engineering, the large orbital overlap can form an efficient carrier channel, overcoming the tunneling barrier. Specifically, by selecting the 2D carbon-based X_(3)C_(2) (X = Cd, Hg, and Zn) metal and the 2D MSi_(2)N_(4) (M = Cr, Hf, Mo, Ti, V, and Zr) semiconductor, we constructed 36 metal/semiconductor contacts. For vdWs contacts, although Ohmic contacts can be formed at the interface, the highest tunneling probability (P TB) is only 3.11%. As expected, the P TB can be significantly improved, as high as 48.73%, when MSi_(2)N_(4), accompanied by surface nitrogen vacancies, forms an interface covalent bond with X_(3)C_(2). Simultaneously, weak FLP and Ohmic contact remain at the covalent-bond-based surface, attributing to the protection of the MSi_(2)N_(4) band-edge electronic states by the outlying Si-N sublayer. Our work provides a promising path for advancing the progress of 2D electronic and photoelectronic devices.
基金the National Natural Science Foundation of China(12275066,11605123,11547103,12074295)。
文摘In 2018, the CMS collaboration reported a di-photon excess at approximately 95.3 GeV with a local significance of 2.8 σ. Interestingly, the CMS collaboration also recently reported a di-tau excess at 95-100 GeV with a local significance of 2.6-3.1 σ. In addition, a bb excess at 98 GeV with a local significance of 2.3 σ was reported from LEP data approximately twenty years ago. In this study, we addressed the interpretation of these excesses together with a light Higgs boson in the next-to-minimal supersymmetric standard model(NMSSM). We conclude that, in the NMSSM, the 95-100 GeV excesses are difficult to be satisfied simultaneously(not possible globally at the 1σ level or simultaneously at the 2σ level). We analyzed two partially-satisfied scenarios: global 2σ and small di-photon. An approximate equation of global fit to the three excesses was derived, and two representative types of surviving samples were analyzed in detail. Given that the mass regions of these excesses are near the Z boson, we also checked the light Higgs boson in the tt-associated channels. The detailed results may be useful for further checking the low-mass-region excesses in the future.
基金Supported by the National Natural Science Foundation of China(NNSFC,11605123)。
文摘Motivated by recent supersymmetry(SUSY)search results,which prefer most SUSY particles to be heavy,and the muon g–2 anomaly,which prefers colorless SUSY particles to be light,we explore the status of a light smuon(the SUSY partner of a left-handed muon lepton)in the next-to-minimal supersymmetric standard model(NMSSM).Assuming colored SUSY particles to be heavy,and considering numerous experimental constraints,including muon g-2,SUSY searches,and dark matter,we scan the parameter space in the NMSSM with Z3-symmetry and check the status of colorless SUSY particles and their possible mass order,paying special attention to the smuon.After calculations and discussions,we find that the surviving samples can be divided into several scenarios,where the mass region and decay information of the smuon are given.Overall,the smuon mass can be approximately 0.1~1.8 TeV.These results may be useful for smuon searches at the LHC and future colliders.
