Ab initio Derivation of Low-Energy Model for Iron-Based Superconductors LaFeAsO and LaFePO(Condensed matter: electronic structure and electrical, magnetic, and optical properties)
Ab initio Derivation of Low-Energy Model for Iron-Based Superconductors LaFeAsO and LaFePO(Condensed matter: electronic structure and electrical, magnetic, and optical properties)
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DOI：
10.1143/jpsj.77.093711
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发表时间：
2008-06
影响因子：
1.7
通讯作者：
Kazuma Nakamura;R. Arita;M. Imada
中科院分区：
文献类型：
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作者：
Kazuma Nakamura;R. Arita;M. Imada
LaFeAsO和LaFePO的有效哈密顿量来源于基于第一性原理计算的下折叠方案，并为新发现的超导体LnFeAsO 1- x fx， Ln = La, Ce, Pr, Nd， Sm和Gd家族提供了见解。扩展哈伯德哈密顿量主要由五重简并铁-3 - d带构造。它们包含有效库仑和交换相互作用的参数，这些参数是由远离费米能级的其他电子的极化所屏蔽的。现场估计的库仑相互作用为2.2-3.3 eV，与最近邻Fe-3 d万尼尔轨道之间的传递积分为0.2-0.3 eV进行了比较，表明电子相关性中等强。发现洪德规则耦合为0.3-0.6 eV。该模型为进一步研究该类材料的物理特性提供了坚实的基础。结果表明，As和P化合物的有效模型具有非常相似的筛选相互作用。
Effective Hamiltonians for LaFeAsO and LaFePO are derived from the downfolding scheme based on first-principles calculations and provide insights for newly discovered superconductors in the family of LnFeAsO 1- x F x , Ln = La, Ce, Pr, Nd, Sm, and Gd. Extended Hubbard Hamiltonians for five maximally localized Wannier orbitals per Fe are constructed dominantly from five-fold degenerate iron-3 d bands. They contain parameters for effective Coulomb and exchange interactions screened by the polarization of other electrons away from the Fermi level. The onsite Coulomb interaction estimated as 2.2–3.3 eV is compared with the transfer integrals between the nearest-neighbor Fe-3 d Wannier orbitals, 0.2–0.3 eV, indicating moderately strong electron correlation. The Hund's rule coupling is found to be 0.3–0.6 eV. The derived model offers a firm basis for further studies on physics of this family of materials. The effective models for As and P compounds turn out to have very similar screened interactions with slight...