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hubbard model on an anisotropic checkerboard lattice at finite temperatures: Magnetic and metal–insulator transitions

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Chinese Physics B 2019年第10期28卷 498-503页

作者： Hai-Di Liu State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and MathematicsChinese Academy of Sciences

We study magnetic and Mott transitions of the hubbard model on the geometrically frustrated anisotropic checkerboard lattice at half filling using cellular dynamical mean-field theory. Phase diagrams over a wide area of the parameter space are obtained by varying the interparticle interaction strength, geometric frustration strength, and temperature. Our results show that frustration and thermal fluctuations play a competing role against the interactions and in general favor a metallic phase without antiferromagnetic order. Due to their interplay, the system exhibits competition between antiferromagnetic insulator, antiferromagnetic metal, paramagnetic insulator, and paramagnetic metal phases in the intermediateinteraction regime. In the strong-interaction limit, which reduces to the Heisenberg model, our result is consistent with previous studies.

关键词： geometrical frustration checkerboard lattice hubbard model

Manipulating hubbard-type Coulomb blockade effect of metallic wires embedded in an insulator

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National Science Review 2023年第3期10卷 127-133页

作者： Xing Yang Zhao-Long Gu Huimin Wang Jing-Jing Xian Sheng Meng Naoto Nagaosa Wen-Hao Zhang Hai-Wen Liu Zi-Heng Ling Kai Fan Zhi-Mo Zhang Le Qin Zhi-Hao Zhang Yan Liang Jian-Xin Li Ying-Shuang Fu School of Physics and Wuhan National High Magnetic Field Center Huazhong University of Science and Technology National Laboratory of Solid State Microstructures and Department of Physics Nanjing University Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences RIKEN Center for Emergent Matter Science(CEMS) Department of Applied Physics University of Tokyo Center for Advanced Quantum Studies Department of Physics Beijing Normal University Collaborative Innovation Center of Advanced Microstructures Nanjing University Hubei Key Laboratory of Gravitation and Quantum Physics Huazhong University of Science and Technology Wuhan Institute of Quantum Technology

Correlated states have emerged in low-dimensional systems owing to enhanced Coulomb *** these states requires atomic-scale characterization and delicate control ***,spectroscopic imaging-scanning tunneling microscopy was employed to investigate the correlated states residing in 1D electrons of the monolayer and bilayer MoSe2 mirror twin boundary(MTB).The Coulomb energies,determined by the wire length,drive the MTB into two types of ground states with distinct respective out-of-phase and in-phase charge *** two ground states can be reversibly converted through a metastable zero-energy state with in situ voltage pulses,which tune the electron filling of the MTB via a polaronic process,substantiated by first-principles *** hubbard model calculation with an exact diagonalization method reveals the ground states as correlated insulators from an on-site U-originated Coulomb interaction,dubbed the hubbard-type Coulomb blockade *** study lays a foundation for understanding and tailoring correlated physics in complex systems.

关键词： STM one-dimensional Coulomb effect electron correlation hubbard

Mott transition in ruby lattice hubbard model

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Chinese Physics B 2019年第5期28卷 256-262页

作者： An Bao Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences

Mott transition in a ruby lattice with fermions described by the hubbard model including on-site repulsive interaction is investigated by combining the cellular dynamical mean-field theory and the continuous-time quantum Monte Carlo algorithm. The effect of temperature and on-site repulsive interaction on the metallic–insulating phase transition in ruby lattice with fermions is discussed based on the density of states and double occupancy. In addition, the magnetic property of each phase is discussed by defining certain magnetic order parameters. Our results show that the antiferromagnetic metal is found at the low temperature and weak interaction region and the antiferromagnetic insulating phase is found at the low temperature and strong interaction region. The paramagnetic metal appears in whole on-site repulsive interaction region when the temperature is higher than a certain value and the paramagnetic insulator appears at the middle scale of temperature and on-site repulsive interaction.

关键词： Mott transition ruby lattice hubbard model cellular dynamical mean-field theory

Dynamical t/U Expansion of the Doped hubbard Model

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Chinese Physics Letters 2024年第3期41卷 73-82页

作者：丁文新俞榕 School of Physics and Material Science Anhui UniversityHefei 230601China Kavli Institute for Theoretical Sciences University of Chinese Academy of SciencesBeijing 100190China Physics Department and Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devices Renmin UniversityBeijing 100872China

We construct a new U(1)slave-spin representation for the single-band hubbard model in the large-U *** mean-field theory in this representation is more amenable to describe both the spin-charge-separation physics of th... 详细信息

关键词： hubbard representation separation

Ground State Property of a One-Dimensional Bose–hubbard Model Using Time-Evolving Body Decimation

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Chinese Physics Letters 2013年第8期30卷 125-128页

作者： OUYANG Sheng-De LIU Jing XIANG Shao-Hua SONG Ke-Hui Department of Physics and Information Engineering Huaihua UniversityHuaihua 418000 Department of Education Science Huaihua UniversityHuaihua 418000

We study the ground state property of the one-dimensional Bose–hubbard model using an imaginary time evolving body decimation *** single-particle density matrix is numerically calculated for a Mott insulating system and a superfluid system *** plotting the chemical potential versus the filling n=N/L for U/J=20 and U/J=0.1,we identify the Mott gap for U/J=20 in filling n=***,we investigate the occupation number of the Bloch state with quasimomentum for a system deep in the Mott phase and in the superfluid phase *** results indicate Bose condensation in the quasimomentum space.

关键词： space hubbard system

Low-Density Ferromagnetism in the hubbard Model

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Chinese Physics Letters 2001年第1期18卷 109-110页

作者： AN Jin GONG Chang-De National Laboratory of Solid State Microstructures and Department of Physics Nanjing UniversityNanjing 210093 Chinese Center of Advanced Science and Technology(World Laboratory) P.O.Box 8730Beijing 100080

We study analytically the stability of the saturated ferromagnetic ground state(the Nagaoka state)of the hubbard model in the low electron density limit with the mean-field *** find that the critical U_(c) is just 4πt,where t is the hopping integral between the nearest neighbours,i.e.,when U is larger than 4πt,the paramagnetic state is unstable with respect to the ferromagnetic state,and vice versa.

关键词： hubbard ferromagnetic saturated

Eigenstate Distribution Fluctuation of a Quenched Disordered Bose–hubbard System in Thermal-to-Localized Transitions

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Chinese Physics Letters 2019年第2期36卷 49-53页

作者： Junjun Xu Yanxing Li Department of Physics University of Science and Technology Beijing

We study the thermalization of a quenched disordered Bose–hubbard system. By considering the eigenstate distribution fluctuation, we show that the thermal to many-body localized transition is always connected to a minimum of this distribution fluctuation. We also observe a Mott-localized regime, where the system fails to thermalize due to the strong on-site repulsion. Lastly, we show how to detect this eigenstate distribution fluctuation in a cold atom system, which is equivalent to measure the Loschmidt echo of the system. Our work suggests a way to measure the thermal-to-localized transitions in experiments, especially for a large system.

关键词： hubbard System in Thermal-to-Localized Transitions Eigenstate Distribution Fluctuation of a Quenched Disordered Bose MBL

Evidence of Phase Separation in the hubbard Model

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Chinese Physics Letters 2000年第5期17卷 365-366页

作者： LUAN Bin-Quan GONG Chang-De National Key Laboratory of Solid States of Microstructure and Department of Physics Nanjing UniversityNanjing 210093

We examine theoretically the possibility of phase separation due to bole aggregation in the background of anti-ferromagneticallyr ordered CuO_(2) *** results which are calculated within a self-consistent mean-field-type approximation give obvious evidence of phase *** conclusions agree with previous numerical results(from exact diagonalization).

关键词： hubbard ferromagnetic separation

Cooper Pairing Near the Boundary in the -U hubbard Model

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Chinese Physics Letters 1997年第9期14卷 698-700页

作者： XU Yuan YAN Xin-zhong Institute of Physics Chinese Academy of SciencesBeijing 100080

The Cooper pairing near the boundary of a superconductor is analyzed by using the linear-response theory The system is described by the square lattice(t,-U)hubbard model occupying half *** half filling,the pairing also corresponds to the antiferromagnetic ordering in the repulsive hubbard *** numerical result clearly shows that,at weak to intermediate coupling(U/t≤l),the boundary exerts strong influence on the order parameter;the weaker the coupling,the deeper the order parameter is suppressed near the *** present scheme is valid in the whole temperature regime of Cooper pairing.

关键词： space. hubbard coupling