The presence of spin-orbit coupling or non-collinear magnetic spin states can have dramatic effects on the ground-state and spectral properties of materials, in particular on the band structure. Here, we develop non-collinear Koopmans-compliant functionals based on Wannier functions and density-functional perturbation theory, targeting accurate spectral properties in the quasiparticle approximation. Our non-collinear Koopmans-compliant theory involves functionals of four-component orbitals densities, that can be obtained from the charge and spin-vector densities of Wannier functions. We validate our approach on four emblematic non-magnetic and magnetic semiconductors where the effect of spin-orbit coupling goes from small to very large: the III-IV semiconductor GaAs, the transition-metal dichalcogenide WSe$_2$, the cubic perovskite CsPbBr$_3$, and the ferromagnetic semiconductor CrI$_3$. The predicted band gaps are comparable in accuracy to state-of-the-art many-body perturbation theory and include spin-dependent interactions and screening effects that are missing in standard diagrammatic approaches based on the random phase approximation. While the inclusion of orbital- and spin-dependent interactions in many-body perturbation theory requires self-screening or vertex corrections, they emerge naturally in the Koopmans-functionals framework.
Koopmans spectral functionals in periodic-boundary conditions
Koopmans光谱泛函旨在同时描述原子、分子、纳米结构和周期晶体的基态性质和带电激发。这是通过用简单但物理动机的轨道密度相关修正来增强标准密度泛函来实现的。这些修正作用于一组定域轨道,在周期系统中,类似于最大定域的Wannier函数。与原始的直接超原胞实现[Phys. Rev. X 8,021051(2018)]不同,我们在这里讨论i)使用显式布里渊区采样的边界码所需的复杂但有效的形式主义,以及ii)使用密度泛函微扰理论计算屏蔽的Koopmans校正。除了提供随系统尺寸的改进的缩放之外,本开发使得利用Koopmans泛函的能带结构的计算简单明了。在开源量子ESTERO分布和应用程序的原型绝缘和半导体系统的实施和讨论。
Koopmans-compliant functionals and their performance against reference molecular data
Koopmans兼容的泛函出现自然从延长的约束分段线性的总能量作为一个函数的电子数到每个分数轨道占领。当应用于近似密度泛函理论时,这些修正引起轨道密度相关的泛函和势。我们表明,Koopmans顺从性的最简单实现提供了准粒子激发的准确估计,并且使总能量泛函几乎或完全不变,即,它们正确地描述了电子的去除或添加,但不一定改变系统内的电子电荷密度分布。然后可以构建修改势能面的附加泛函,包括例如Perdew-Zunger校正。这些泛函变得完全无单电子自相互作用,并且与所有符合库普曼的泛函一样,近似无多电子自相互作用。我们详细讨论了这些不同的配方,并提供了广泛的基准参考G2-1组中的55个分子,使用Koopmans兼容的泛函从局部密度或广义梯度近似构建。在所有情况下,我们发现优良的性能,在电子性能,可比或改进的多体微扰理论,如G $_0$ W $_0$和自洽GW,在成本的一小部分,并在一个变分的框架,也提供了能源衍生物。结构性质和原子化能量保持或略微提高了基本密度泛函近似的准确性(注:补充材料包含在源代码中)。
Exchange constants and spin waves of the orbital ordered, non-collinear spinel MnV$_2$O$_4$
本文利用磁力理论和密度泛函理论的局域自旋密度近似,结合Hubbard相互作用U的修正,研究了MnV $_2$ O $_4$的交换常数.我们得到了尖晶石中钒原子三种不同轨道排列的交换。然后,我们将交换常数映射到具有单离子各向异性的海森堡模型,并求解尖晶石的非共线低温相的自旋波激发。单离子各向异性参数是由原子多重态精确对角化程序计算得到的,考虑了晶体场分裂和自旋轨道耦合的影响。我们发现我们的轨道有序设置与以前报道的实验自旋波中子散射确定的自旋波之间的良好协议。因此,我们可以从文献中存在的各种建议中确定正确的轨道顺序。
Interplay of Orbital Degeneracy and Vacancies in Stabilizing Collinear Magnetic Order in Cr$_{1+δ}$Te$_2$
Indian Association for the Cultivation of Science(印度科学文化研究所);S. N. Bose National Centre for Basic Sciences(S.N. 玻色基础科学国家中心);Indian Institute of Technology Goa(印度理工学院果阿分校);Rutherford Appleton Laboratory(卢瑟福·阿普尔顿实验室);Uppsala University(乌普萨拉大学);University of Johannesburg(约翰内斯堡大学)
Integrating Deep-Learning-Based Magnetic Model and Non-Collinear Spin-Constrained Method: Methodology, Implementation and Application
AI for Science Institute(人工智能科学研究院);Graduate School of China Academy of Engineering Physics(中国工程物理研究院研究生院);International School of Materials Science and Engineering, Wuhan University of Technology(武汉理工大学材料科学与工程学院国际学院);DP Technology(帝恩普科技有限公司);HEDPS, CAPT, School of Physics and College of Engineering, Peking University(北京大学物理学院与工学院、高能量密度物理教育部重点实验室、前沿交叉科学研究中心);Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University(武汉大学物理科学与技术学院、人工微结构和介观物理国家重点实验室);Department of Materials Science and Engineering, Carnegie Mellon University(卡内基梅隆大学材料科学与工程系)
Engineering photomagnetism in collinear van der Waals antiferromagnets
Radboud University, Institute for Molecules and Materials(拉德堡德大学分子与材料研究所);HFML-FELIX;Institute of Physics, University of Amsterdam(阿姆斯特丹大学物理研究所);Department of Physics, Technische Universität Dortmund(多特蒙德工业大学物理系);Research Center Future Energy Materials and Systems(未来能源材料与系统研究中心);King’s College London, Theory and Simulation of Condensed Matter(伦敦国王学院凝聚态理论模拟)
Nonlinear Magnetic Orbital Hall Effect Induced by Spin-Orbit Coupling
Singapore University of Technology and Design(新加坡科技设计大学);Beihang University(北京航空航天大学);Yanshan University(燕山大学);Fudan University(复旦大学);Lanzhou University(兰州大学);The Hong Kong Polytechnic University(香港理工大学)
Orbital altermagnetism on the kagome lattice and possible application to $A$V$_3$Sb$_5$
The Grainger College of Engineering, University of Illinois Urbana-Champaign(伊利诺伊大学厄巴纳-香槟分校格雷恩格工程学院);Anthony J. Leggett Institute for Condensed Matter Theory, The Grainger College of Engineering, University of Illinois Urbana-Champaign(伊利诺伊大学厄巴纳-香槟分校格雷恩格工程学院安东尼·J·利盖特凝聚态理论研究所);Department of Chemical Engineering and Materials Science, University of Minnesota(明尼苏达大学化学工程与材料科学系)
Spin-orbit coupling effects in altermagnets: Interplay of weak spin and orbital ferromagnetism with relativistic splitting of electron states
Charles University(查理大学);Donostia International Physics Center (DIPC)(圣塞巴斯蒂安国际物理中心);Universidad del País Vasco (UPV-EHU)(巴斯克大学);IKERBASQUE, Basque Foundation for Science(伊克尔巴斯科奎,巴斯克科学基金会)
Anomalous Hall enhancement in fully compensated non-collinear antiferromagnetic Cr-doped Mn3Sn
National University of Singapore(新加坡国立大学);National University of Singapore (Chongqing) Research Institute(新加坡国立大学(重庆)研究院);Nanyang Technological University(南洋理工大学);Nanjing University(南京大学);Central South University(中南大学)
Nature of field-induced transitions and hysteretic magnetoresistance in non-collinear antiferromagnet EuIn2As2
Institute of Low Temperature and Structure Research, Polish Academy of Sciences(波兰科学院低温结构研究所);International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences(波兰科学院磁顶国际研究中心物理研究所);Università degli Studi di Milano(米兰大学);Institute of Nuclear Physics, Polish Academy of Sciences(波兰科学院核物理研究所);Institute of Molecular Physics, Polish Academy of Sciences(波兰科学院分子物理研究所)
Electronic and magnetic structures of ternary iron selenides AFe$_2$Se$_2$ (A=K, Cs, or Tl)
通过第一性原理电子结构计算,我们发现三元铁硒化物AFe $_2$ Se $_2$(A=K,Cs,或Tl)的基态为双共线反铁磁有序,其中Fe局域磁矩($\sim2.8μ_B$)沿Fe-Fe正方晶格的一个对角线方向铁磁排列,而沿另一个对角线方向反铁磁排列.这种双共线反铁磁序是由Se $4p$轨道介导的最近邻、次最近邻和次最近邻超交换相互作用之间的相互作用引起的。