CPM Seminar

Correlation Effects in FeAs-based Compounds Studied by LDA+Gutzwiller Method

Zhong Fang

Institute of Physics
Chinese Academy of Sciences

I will first introduce our newly developed LDA+Gutzwiller method, in which the Gutzwiller variational approach is incorporated with the density functional theory (DFT) through the generalized Kohn-Sham formalism, such that orbital fluctuations can be treated from ab initio. We will show that its quality for ground state determination is as accurate as dynamic mean field theory (DMFT), and yet its computational cost is as cheap as LDA+U. Then we will concentrate on FeAs-based compounds, which are typical multi-orbital correlated system. Various corrected properties beyond LDA (or GGA), such as Fe-As distance, soft phonon, and Fermi surface shape, will be discussed based on the calculations by LDA+Gutzwiller. The inter-orbital Hund's coupling J rather than U plays crucial roles for the physical properties of FeAs-compounds.

References:
[1] X. Y. Deng, X. Dai, Z. Fang, EPL 83, 37008 (2008).
[2] G. T. Wang, X. Dai, Z. Fang, PRL 101, 066403 (2008).
[3] X. Y. Deng, L. Wang, X. Dai, Z. Fang, PRB 79, 075114 (2009).
[4] G. T. Wang, X. Dai, Z. Fang, Cond-mat:/0903.1385 (2009).