本文报道了A $_2$ IrO $_4$(A=Sr,Ba)的{\it Ab initio}分析。基于动力学平均场理论,求解了Ir 5 $d$ $t_{2g}$流形的有效Hubbard型模型. A=Sr和Ba的结果正确地再现了顺磁性金属在低于Néel温度$T_N$时连续转变为绝缘体的过程。这些化合物不属于莫特绝缘体,而属于斯莱特绝缘体。然而,绝缘间隙打开的Neel顺序和显着的带重正化的协同作用,这也表现为在量子临界附近的顺磁相的2D坏金属行为。
英文摘要:
{\it Ab initio} analyses of A$_2$IrO$_4$ (A=Sr, Ba) are presented. Effective Hubbard-type models for Ir 5$d$ $t_{2g}$ manifolds downfolded from the global band structure are solved based on the dynamical mean-field theory. The results for A=Sr and Ba correctly reproduce paramagnetic metals undergoing continuous transitions to insulators below the Néel temperature $T_N$. These compounds are classified not into Mott insulators but into Slater insulators. However, the insulating gap opens by a synergy of the Neel order and significant band renormalization, which is also manifested by a 2D bad metallic behavior in the paramagnetic phase near the quantum criticality.
Ab initio Evidence for Strong Correlation Associated with Mott Proximity in Iron-based Superconductors
我们预测,发现的铁基超导体附近的d6配置(5 Fe 3d轨道填充6个电子)位于一个意想不到的大圆顶的相关电子物质在d5(即,半填充)的莫特绝缘体为中心的脚。这是基于多变量变分蒙特卡罗从头算低能量模型的结果推导的向下折叠。D5莫特接近延伸到随后出现的非相干金属,轨道微分由于莫特物理和洪德规则耦合,其次是反铁磁量子临界,根据现有的实验定量。
Non-local Coulomb correlations in pure and electron-doped ${\mathrm{Sr}}_{2}{\mathrm{IrO}}_{4}$: spectral functions, Fermi surface and pseudogap-like spectral weight distributions from oriented cluster dynamical mean field theory
Unexpectedly large electron correlation measured in Auger spectra of ferromagnetic iron thin films: orbital-selected Coulomb and exchange contributions
Theoretical study of insulating mechanism in multi-orbital Hubbard models with a large spin-orbit coupling: Slater versus Mott scenario in Sr$_2$IrO$_4$
Non-local Coulomb interactions and metal-insulator transition in Ti$_2$O$_3$: a cluster LDA+DMFT approach
我们提出了Ti $_2$ O $_3$金属-绝缘体转变的从头计算量子理论。采用最近发展起来的集团LDA+DMFT方案来描述该化合物的多体特征。对于任何合理的库仑相互作用值,传统的单点DMFT都不能再现低温绝缘相。结果表明,非定域库仑相互作用和Ti-Ti对间强的化学键是Ti $_2$ O $_3$小能隙绝缘基态的起源.
Magnetic fluctuations and superconducting pairing in $\varepsilon$-iron
M. N. Miheev Institute of Metal Physics, Russian Academy of Sciences(俄罗斯科学院 M.N. 米赫耶夫金属物理研究所);Ural Federal University(乌拉尔联邦大学);Moscow Institute of Physics and Technology(莫斯科物理技术学院)
Derivation of Static Low-Energy Effective Models by ab initio Downfolding Method without Double Counting of Coulomb Correlations: Application to SrVO3, FeSe and FeTe
Ab initio Derivation of Low-Energy Model for Alkali-Cluster-Loaded Sodalites
利用{ \em ab initio}向下折叠的方法,导出了一个描述碱金属团簇负载的方钠石磁性的有效低能模型。首先,我们构造了一个扩展的哈伯德模型的最大局部化Wannier函数。用约束无规相近似计算了{ \em Ab initio}屏蔽库仑相互作用和交换相互作用。我们发现该系统处于强耦合区,因此海森伯模型是扩展的哈伯德模型的低能模型。我们得到反铁磁耦合$\sim$ $O$(10 K),与实验的自旋磁化率的温度依赖性是一致的。讨论了在推导推广的哈伯德模型时考虑屏蔽效应的重要性。
Ab-initio prediction of magnetoelectricity in infinite-layer CaFeO2 and MgFeO2
基于密度泛函的模拟研究了铁基氧化物的磁电效应,发现铁基氧化物具有独特的层状结构。我们从理论上预测CaFeO 2是一个有前途的磁电,显示磁控大电极化的强度,甚至可能高于室温。磁和偶极自由度之间的交叉耦合的需要,作为主要成分,铁网站的自旋轨道耦合和自旋依赖的O p - Fe d杂化,以及与非中心对称的点群和特殊的几何结构,其特征在于由“扁平”的FeO 4四面体的结构约束。为了增强磁电效应,我们进行了材料设计,导致一种新的和优化的系统,MgFeO 2,其中较大的O 4四面体畸变导致更强的极化。
First-principles Calculation of Effective Onsite Coulomb Interaction of 3d Transition Metals: Constrained Local Density Functional Approach with Maximally Localized Wannier Function
Superconductivity in Electron Liquids: Precision Many-Body Treatment of Coulomb Interaction
Institute of Theoretical Physics, Chinese Academy of Sciences(中国科学院理论物理研究所);Department of Physics, University of Massachusetts, Amherst(马萨诸塞大学阿默斯特分校物理系);Institute of Physics, Chinese Academy of Sciences(中国科学院物理研究所);Center for Computational Quantum Physics, Flatiron Institute(西蒙斯平顿研究所计算量子物理中心);Department of Physics, Columbia University(哥伦比亚大学物理系)
Comment on 2501.17230 and 2502.00103 "Phonon-mediated electron attraction in SrTiO3 via the generalized Frohlich and deformation potential mechanisms" and "Theory of ab initio downfolding with arbitrary range electron-phonon coupling"
Triplet pairing, orbital selectivity and correlations in Iron-based superconductors
University of Cincinnati(辛辛那提大学);Max-Planck-Institut für Festkörperforschung(马克斯·普朗克固体研究所);Rutgers University(罗格斯大学);Royal Holloway, University of London(伦敦大学皇家霍洛威学院)
Coulomb repulsion and correlation strength in LaFeAsO from Density Functional and Dynamical Mean-Field Theories
本文采用LDA+DMFT(Local Density Approximation combined with Dynamical Mean Field Theory)计算方法,计算了新型高T $_c$铁氧磷氧化合物的母体化合物LaFeAsO的光谱性质。采用Wannier函数体系中的\textit {第一性原理}约束密度泛函理论方法,计算了铁3d电子的库仑排斥$U$和Hund交换$J$参数.所得值强烈依赖于计算中考虑的状态的数量:当包括具有相应带的$2p$、As- $4p$和Fe-3d轨道的全集时,计算结果为$U=3÷$ 4 eV和J=0.8 eV.当基组仅限于Fe-3d轨道和能带时,计算得到的参数值$F^0$ =0.8 eV,$J$ =0.5 eV。然而,DMFT计算与这两个参数集和相应的基函数的选择,导致弱相关的电子结构,这是与实验的X射线和光电子能谱。