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大学物理 1991年第1期10卷 44-46页

作者：邹良剑中国科技大学

本文把薛定谔方程视为扩散系数是虚数的扩散方程，在波函数初值分别为δ函数和高斯函数的假定下求解方程，讨论了所得结果的物理意义；发现波函数ψ（ｘ，ｔ）正对应于自由粒子的传播子和粒子通过高斯型狭缝的传播子，结果所含信息比预... 详细信息

本文把薛定谔方程视为扩散系数是虚数的扩散方程，在波函数初值分别为δ函数和高斯函数的假定下求解方程，讨论了所得结果的物理意义；发现波函数ψ（ｘ，ｔ）正对应于自由粒子的传播子和粒子通过高斯型狭缝的传播子，结果所含信息比预料的要多．

关键词：薛定谔方程扩散系数扩散方程

多轨道Hubbard模型的隶玻色子数值算法研究

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物理学报 2012年第1期61卷 422-433页

作者：全亚民刘大勇邹良剑中国科学院固体物理研究所物质计算科学研究室合肥230031

通过综合模式搜索法、广义Lagrange乘子法、以及转轴法等多种数值方法,建立了一套针对多轨道Hubbard模型隶玻色子解法的数值优化方法.该数值方法能够在考虑晶场劈裂、轨道间跳跃以及真实能带结构基础上,利用隶玻色子方法计算实际关联电... 详细信息

通过综合模式搜索法、广义Lagrange乘子法、以及转轴法等多种数值方法,建立了一套针对多轨道Hubbard模型隶玻色子解法的数值优化方法.该数值方法能够在考虑晶场劈裂、轨道间跳跃以及真实能带结构基础上,利用隶玻色子方法计算实际关联电子材料的性质.首先利用该方法计算了两轨道体系的.Mott金属一绝缘体转变性质,得到了与目前已有工作一致的结果;然后利用该方法讨论了Coulomb关联对三轨道体系Na_xCoO_2的影响.结果表明:在中间关联情况下由eg轨道形成的六个小Fermi面消失,原因是由于电子关联导致该轨道上的空穴数随U减少.这些结果也证实了算法的正确性和有效性.

关键词：多轨道Hubbard模型隶玻色子 Mott转变 Na_xCoO_2

Electrical Control of Edge Magnetism in Two-Dimensional Buckled Honeycomb Lattice

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Chinese Physics Letters 2014年第9期31卷 144-147页

作者：鲍伟成邹良剑 Key Laboratory of Materials Physics Institute of Solid State Physics Chinese Academy of Sciences Hefei 230031 Department of Physics University of Science and Technology of China Hefei 230026

We theoretically study indirect spin coupling strength between two magnetic impurities located on honeycomb Kane-Mele zigzag ribbon （KMZR） with periodic and open boundary （PB and OB）. We show that spin interaction J in PB ribbons displays an AFM-FM oscillating behavior with increasing the staggered potential and electron density, and approaches to maximum at the edges. While the spin coupling in OB KMZR shows a trivial smooth AFM coupling with varying staggered potential. Such a novel J（ A） behavior is the combining effect of finite size, topological edge states and inversion symmetry breaking induced by the staggered potential. We propose that one could control the edge magnetism electrically in two-dimensional buckled honeycomb materials, e.g., silicence, germanene and stanene.

关键词： Honeycomb structures

Electronic States and Spatial Charge Distribution of Single Mn Impurity in Diluted Magnetic Semiconductors

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Chinese Physics Letters 2006年第6期23卷 1588-1591页

作者：王维华邹良剑 Key Laboratory of Materials Physics Institute of Solid State Physics Chinese Academy of Sciences PO Box 1129 Hefei 230031 Graduate School of the Chinese Academy of Sciences Beijing 100049

The electronic and magnetic properties as well as the spatial charge distribution of single Mn impurity in Ⅲ-Ⅴ diluted magnetic semiconductors are obtained when the degeneracy of the p orbits contributed from the four nearest-neighbouring As（N） atoms is taken into account. We show that in the ground state, the Mn spin is strongly antiferromagnetically coupled to the surrounding As（N） atoms when the p - d hybridization Vpd is large and both the hole level Ev and the impurity level Ed are close to the Fermi energy. The spatial charge distribution of the Mn acceptor in the （110） plane is non-spherically symmetric, in good agreement with the recent STM images.

关键词： FERROMAGNETISM

Effects of anharmonic lattice distortion on orbital and magnetic orderings in KCuF_3

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Chinese Physics B 2009年第10期18卷 4497-4505页

作者：刘大勇陈东猛邹良剑 Key Laboratory of Materials Physics Institute of Solid State Physics Chinese Academy of Sciences Graduate School of the Chinese Academy of Sciences College of Physics Science and Technology China University of Petroleum

Lattice, magnetic and orbital structures in KCuF3 are self-consistently determined by our cluster self-consistent field approach based on a spin-orbital-lattice Hamiltonian. Two stable structures are obtained and found to be degenerate, which confirms the presence of the coexistent phases observed experimentally. We clearly show that due to the inherent frustration, the ground state of the system only with the superexchange interaction is degenerate; while the Jahn-Teller distortion, especially the anharmonic effect, stabilizes the orbital ordered phase at about 23% in the x2-y2 orbit and at 77% in the 3z2-r2 orbit. Meanwhile the magnetic moment of Cu is considerably reduced to 0.56μB, and magnetic coupling strengths are highly anisotropic, Jx/Jxy ≈ 18. These results are in good agreement with the experiments, implying that the anharmonic Jahn-Teller effect plays an essential role in stabilising the orbital ordered ground state of KCuF3.

关键词： orbital ordering KCuF3 Jahn Teller effect anharmonic lattice distortion

Orbital Order and Orbital Excitations in Degenerate Itinerant Electron Systems

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Chinese Physics Letters 2009年第9期26卷 243-246页

作者：卢峰宋筠陈东猛邹良剑 Key Laboratory of Materials Physics Institute of Solid State Physics Chinese Academy of Sciences PO Box 1129 Hefei 230031 Graduate School of the Chinese Academy of Sciences Beijing 100190 Department of Physics Beijing Normal University Beijing 100875 College of Physics Science and Technology China University of Petroleum Dongying 257061

We present a theory of orbital ordering in orbital-degenerate itinerant electron systems. The orbital instability in a two-orbital degenerate Hubbard model is investigated in the random phase approximation （RPA）. After demonstrating the criteria for the formation of orbital ordering or the orbital density wave ordering, we find that the orbital and the spin-orbital collective excitation spectra in the ferro-orbital ordered phase exhibit finite gaps. The possible application of the present theory in orbital-ordered 4d compounds is also discussed.

关键词： sea surface nonliear interaction numerical method

Non-Adiabatic Effects of Superconductor Silane under High Pressure

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Chinese Physics Letters 2010年第8期27卷 194-196页

作者：范巍王江龙邹良剑曾雉 Key Laboratory of Materials Physics Institute of Solid State Physics Hefei Institutes of Physical Sciences Chinese Academy of Sciences Hefei 230031 Department of Physics Hebei University Baoding 071002

We present the investigations of non-adiabatic effects by including vertex corrections in the standard Eliashberg theory and show that high phonon frequency is unfavorable to superconductivity in the regime of strong vertex correction. This means that it is hard to find high-transition-temperature superconductors in the compounds with light elements if the non-adiabatic effects are strong. The interplay interaction between non-adiabatic effect and Coulomb interaction makes the transition temperature of silane superconductor not so high as predicted by the standard Eliashberg theory.

关键词： Standards Standardizing Temperature

Variational Monte Carlo study of the nematic state in iron-pnictide superconductors with a five-orbital model

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Chinese Physics B 2015年第1期24卷 109-113页

作者：郑晓军黄忠兵邹良剑 Key Laboratory of Materials Physics Institute of Solid State Physics Chinese Academy of Sciences Faculty of Physics and Electronic Technology Hubei University Beijing Computational Science Research Center Department of Physics University of Science and Technology of China

We perform a variational Monte Carlo study of the nematic state in iron-pnictide superconductors within a realistic five-orbital model. Our numerical results show that the nematic state, formed by introducing an anisotropic hopping order into the projected wave function, is not stable unless the off-site Coulomb interaction V exceeds a critical value. This demonstrates that V plays a key role in forming the nematic state in iron-pnictide superconductors. In the nematic state,the orbital order and the anisotropic spin correlations are consistent with the experimental observations. We argue that the experimentally observed anisotropic magnetic couplings and structural transition are associated with the nematic state and can be understood in a unified framework.

关键词： iron-pnictide superconductors nematic state off-site Coulomb interaction variational Monte Carlo simulation

Magnetic Long-Range Order and Colossal Magnetoresistance Effect in Double Exchange Ladders

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Chinese Physics Letters 2001年第9期18卷 1264-1267页

作者：马冬梅邹良剑 Institute of Solid State Physics Chinese Academy of SciencesHefei 230031 National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093

By applying Bogoliubov's ineguality to double-exchange(DE) ladders, we show that the ferromagnetic(FM) order is absent in the new DE systems at finite temperatures. The incorporation of Jahn-Teller electron-phonon coupling, orbital degeneracy and on-site Coulomb interaction with the DE interaction do not preserve these orders. The long-wavelength thermal fluctuations of the spins oversome the DEFM correlation and destroy the FM orders. The implication of the absence of FM order on the transport of the DE ladders is discussed.

关键词： orders interaction ladder

Interplay of iron and rare-earth magnetic order in rare-earth iron pnictide superconductors under magnetic field

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Chinese Physics B 2016年第2期25卷 446-453页

作者：杨雷雷刘大勇陈东猛邹良剑 Key Laboratory of Materials Physics Institute of Solid State Physics Chinese Academy of Sciences College of Science China University of Petroleum Department of Physics University of Science and Technology of China

The magnetic properties of iron pnictide superconductors with magnetic rare-earth ions under strong magnetic field are investigated based on the cluster self-consistent field method. Starting from an effective Heisenberg model, we present the evolution of magnetic structures on magnetic field in RFeAsO（R = Ce, Pr, Nd, Sm, Gd, and Tb） and RFe_2As_2（R =Eu） compounds. It is found that spin-flop transition occurs in both rare-earth and iron layers under magnetic field, in good agreement with the experimental results. The interplay between rare-earth and iron spins plays a key role in the magneticfield-driven magnetic phase transition, which suggests that the rare-earth layers can modulate the magnetic behaviors of iron layers. In addition, the factors that affect the critical magnetic field for spin-flop transition are also discussed.

关键词： iron pnictide superconductors rare-earth magnetic field spin-flop transition