We investigate the hole-doped Hubbard model on a honeycomb lattice using a fermionic projected entangled pair states(f PEPS)method.Our study reveals the presence of quasi-long-range order of Cooper pairs,characterized...We investigate the hole-doped Hubbard model on a honeycomb lattice using a fermionic projected entangled pair states(f PEPS)method.Our study reveals the presence of quasi-long-range order of Cooper pairs,characterized by powerlaw decay of correlation functions with exponents K>1.We further analyze the competing phases of superconductivity,specifically the antiferromagnetic(AFM)order and the charge density wave(CDW)order.Our results show that there are domain wall structures when the hole dopingδis small and the Coulomb parameter U is large.However,these structures disappear as we increase the hole dopingδor decrease U.Furthermore,for small hole doping,the system exhibits AFM order,which diminishes forδ>0.05.Conversely,as the doping level increases,the CDW order gradually decreases.Notably,a considerable CDW order persists even at higher doping levels.These findings suggest a progressive suppression of the AFM order and a growing prominence of the CDW order with increasingδ.展开更多
We construct a new U(1)slave-spin representation for the single-band Hubbard model in the large-U limit.The mean-field theory in this representation is more amenable to describe both the spin-charge-separation physics...We construct a new U(1)slave-spin representation for the single-band Hubbard model in the large-U limit.The mean-field theory in this representation is more amenable to describe both the spin-charge-separation physics of the Mott insulator at half-filling and the strange metal behavior at finite doping.展开更多
We construct an integrable 1D extended Hubbard model within the framework of the quantum inverse scattering method.With the help of the nested algebraic Bethe ansatz method,the eigenvalue Hamiltonian problem is solved...We construct an integrable 1D extended Hubbard model within the framework of the quantum inverse scattering method.With the help of the nested algebraic Bethe ansatz method,the eigenvalue Hamiltonian problem is solved by a set of Bethe ansatz equations,whose solutions are supposed to give the correct energy spectrum.展开更多
Vanadium dioxide VO_(2) is a strongly correlated material that undergoes a metal-to-insulator transition around 340 K.In order to describe the electron correlation effects in VO_(2), the DFT+U method is commonly emplo...Vanadium dioxide VO_(2) is a strongly correlated material that undergoes a metal-to-insulator transition around 340 K.In order to describe the electron correlation effects in VO_(2), the DFT+U method is commonly employed in calculations.However, the choice of the Hubbard U parameter has been a subject of debate and its value has been reported over a wide range. In this paper, taking focus on the phase transition behavior of VO_(2), the Hubbard U parameter for vanadium oxide is determined by using the quasi-harmonic approximation(QHA). First-principles calculations demonstrate that the phase transition temperature can be modulated by varying the U values. The phase transition temperature can be well reproduced by the calculations using the Perdew–Burke–Ernzerhof functional combined with the U parameter of 1.5eV. Additionally,the calculated band structure, insulating or metallic properties, and phonon dispersion with this U value are in line with experimental observations. By employing the QHA to determine the Hubbard U parameter, this study provides valuable insights into the phase transition behavior of VO_(2). The findings highlight the importance of electron correlation effects in accurately describing the properties of this material. The agreement between the calculated results and experimental observations further validates the chosen U value and supports the use of the DFT+U method in studying VO_(2).展开更多
A recently discovered family of kagome lattice materials,AV_(3)Sb_(5)(A=K,Rb,Cs),has attracted great interest,especiallyin the debate over their dominant superconducting pairing symmetry.To explore this issue,we study...A recently discovered family of kagome lattice materials,AV_(3)Sb_(5)(A=K,Rb,Cs),has attracted great interest,especiallyin the debate over their dominant superconducting pairing symmetry.To explore this issue,we study the superconductingpairing behavior within the kagome-lattice Hubbard model through the constrained path Monte Carlo method.It isfound that doping around the Dirac point generates a dominant next-nearest-neighbor-d pairing symmetry driven by on-siteCoulomb interaction U.However,when considering the nearest-neighbor interaction V,it may induce nearest-neighbor-ppairing to become the preferred pairing symmetry.Our results provide useful information to identify the dominant superconductingpairing symmetry in the AV_(3)Sb_(5)family.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12134012 and 12104433)。
文摘We investigate the hole-doped Hubbard model on a honeycomb lattice using a fermionic projected entangled pair states(f PEPS)method.Our study reveals the presence of quasi-long-range order of Cooper pairs,characterized by powerlaw decay of correlation functions with exponents K>1.We further analyze the competing phases of superconductivity,specifically the antiferromagnetic(AFM)order and the charge density wave(CDW)order.Our results show that there are domain wall structures when the hole dopingδis small and the Coulomb parameter U is large.However,these structures disappear as we increase the hole dopingδor decrease U.Furthermore,for small hole doping,the system exhibits AFM order,which diminishes forδ>0.05.Conversely,as the doping level increases,the CDW order gradually decreases.Notably,a considerable CDW order persists even at higher doping levels.These findings suggest a progressive suppression of the AFM order and a growing prominence of the CDW order with increasingδ.
基金supported by Startup Fund of Anhui University(Grant No.S020118002/002)support from the Kavli Institute for Theoretical Sciences+1 种基金supported by the National Key R&D Program of China(Grant No.2023YFA1406500)the National Science Foundation of China(Grant Nos.12334008 and 12174441)。
文摘We construct a new U(1)slave-spin representation for the single-band Hubbard model in the large-U limit.The mean-field theory in this representation is more amenable to describe both the spin-charge-separation physics of the Mott insulator at half-filling and the strange metal behavior at finite doping.
基金Financial support from the National Natural Science Foundation of China(Grant Nos.12105221,12175180,12074410,12047502,11934015,11975183,11947301,11775177,11775178 and 11774397)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB33000000)+4 种基金the Shaanxi Fundamental Science Research Project for Mathematics and Physics(Grant No.22JSZ005)the Major Basic Research Program of Natural Science of Shaanxi Province(Grant Nos.2021JCW-19,2017KCT-12 and 2017ZDJC-32)the Scientific Research Program Funded by the Shaanxi Provincial Education Department(Grant No.21JK0946)the Beijing National Laboratory for Condensed Matter Physics(Grant No.202162100001)the Double First-Class University Construction Project of Northwest University is gratefully acknowledged.
文摘We construct an integrable 1D extended Hubbard model within the framework of the quantum inverse scattering method.With the help of the nested algebraic Bethe ansatz method,the eigenvalue Hamiltonian problem is solved by a set of Bethe ansatz equations,whose solutions are supposed to give the correct energy spectrum.
基金supported by the National Natural Science Foundation of China (Grant Nos.21933006 and 21773124)the Fundamental Research Funds for the Central Universities Nankai University (Grant Nos.010-63233001,63221346,63213042,and ZB22000103)+1 种基金the support from the China Postdoctoral Science Foundation (Grant No.2021M691674)the Hefei National Laboratory for Physical Sciences at the Microscale (Grant No.KF2020105)。
文摘Vanadium dioxide VO_(2) is a strongly correlated material that undergoes a metal-to-insulator transition around 340 K.In order to describe the electron correlation effects in VO_(2), the DFT+U method is commonly employed in calculations.However, the choice of the Hubbard U parameter has been a subject of debate and its value has been reported over a wide range. In this paper, taking focus on the phase transition behavior of VO_(2), the Hubbard U parameter for vanadium oxide is determined by using the quasi-harmonic approximation(QHA). First-principles calculations demonstrate that the phase transition temperature can be modulated by varying the U values. The phase transition temperature can be well reproduced by the calculations using the Perdew–Burke–Ernzerhof functional combined with the U parameter of 1.5eV. Additionally,the calculated band structure, insulating or metallic properties, and phonon dispersion with this U value are in line with experimental observations. By employing the QHA to determine the Hubbard U parameter, this study provides valuable insights into the phase transition behavior of VO_(2). The findings highlight the importance of electron correlation effects in accurately describing the properties of this material. The agreement between the calculated results and experimental observations further validates the chosen U value and supports the use of the DFT+U method in studying VO_(2).
基金supported by Beijing Natural Science Foundation(Grant No.1242022).The numerical simulations in this work were performed at HSCC of Beijing Normal University.
文摘A recently discovered family of kagome lattice materials,AV_(3)Sb_(5)(A=K,Rb,Cs),has attracted great interest,especiallyin the debate over their dominant superconducting pairing symmetry.To explore this issue,we study the superconductingpairing behavior within the kagome-lattice Hubbard model through the constrained path Monte Carlo method.It isfound that doping around the Dirac point generates a dominant next-nearest-neighbor-d pairing symmetry driven by on-siteCoulomb interaction U.However,when considering the nearest-neighbor interaction V,it may induce nearest-neighbor-ppairing to become the preferred pairing symmetry.Our results provide useful information to identify the dominant superconductingpairing symmetry in the AV_(3)Sb_(5)family.
