Density functional study of orbital-selective magnetism in FeAs-based superconductors

Hyungju Oh; Donghan Shin; Hyoung Joon Choi

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arXiv · 1012.2224

Density functional study of orbital-selective magnetism in FeAs-based superconductors

Hyungju Oh·Donghan Shin·Hyoung Joon Choi

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Abstract

We performed spin-polarized density functional calculations of lanthanide-series (Ln) iron oxypnictides LnFeAsO (Ln=La, Ce, Pr, Nd, Sm, and Gd) with constrained Fe magnetic moments, finding that in-plane dxy and out-of-plane dyz orbital characters are preferred for small Fe magnetic moments. Comparison of LnFeAsO compounds shows that the antiferromagnetism (AFM) from the Fe dxy orbital is itinerantly driven by orbital-dependent Fermi-surface nesting while AFM from the Fe dyz orbital is driven by superexchange mechanism. The Fe magnetic moments of the two orbital characters show different coupling strengths to Fermi-surface electrons orbital-selectively, suggesting that they may play different roles in superconductivity and in AFM, and making d orbital characters of the magnetic moment resolvable by measuring the electronic structures.

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Hyungju Oh, Donghan Shin, Hyoung Joon Choi. 2010-12-10. Density functional study of orbital-selective magnetism in FeAs-based superconductors. https://arxiv.org/abs/1012.2224

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