Ab initio Low-Dimensional Physics Opened Up by Dimensional Downfolding: Application to LaFeAsO

作者：Nakamura Kazuma^*; Yoshimoto Yoshihide; Nohara Yoshiro; Imada Masatoshi

来源：Journal of the Physical Society of Japan, 2010, 79(12): 123708.

DOI：10.1143/JPSJ.79.123708

• first-principles calculation
• effective low-dimensional Hamiltonian
• constrained RPA method
• dimensional downfolding
• anisotropic low-dimensional system
• LaFeAsO

An ab initio downfolding method is formulated to construct low-dimensional models for correlated electrons. In addition to band downfolding by a constrained random phase approximation formulated for 3D models, screening away from the target layer (chain) is further involved. Eliminating the off-target degrees of freedom, namely, dimensional downfolding, yields ab initio low-dimensional models. The method is applied to derive a 2D model for the layered superconductor LaFeAsO, where interlayer screening crucially makes the effective interaction short-ranged and reduces the onsite Coulomb interactions by 10-20% compared with the 3D model for the five iron-3d orbitals.

• 出版日期2010-12