%A Hirayama,Motoaki
%A Nomura,Yusuke
%A Arita,Ryotaro
%D 2022
%J Frontiers in Physics
%C
%F
%G English
%K nickelate superconductivity,Density Functional Theory,GW approximation,ab initio downfolding,multi-orbital Hubbard model
%Q
%R 10.3389/fphy.2022.824144
%W
%L
%M
%P
%7
%8 2022-February-23
%9 Original Research
%#
%! GW-based downfolding for nickelate superconductors
%*
%<
%T Ab Initio Downfolding Based on the GW Approximation for Infinite-Layer Nickelates
%U https://www.frontiersin.org/articles/10.3389/fphy.2022.824144
%V 10
%0 JOURNAL ARTICLE
%@ 2296-424X
%X We derive an effective three-orbital model for the infinite-layer nickelates based on the band structure obtained by the GW approximation (GWA), where we consider the Ni 3dx2−y2 and O 2p orbitals forming the σ-bond. In the GWA, the self-energy correction to the local density approximation (LDA) increases the energy difference between Ni 3dx2−y2 and O 2p, which reduces the bandwidth of the antibonding 3dx2−y2 orbitals. The isolation of the Ni 3dx2−y2 around the Fermi level suppresses the screening effect. As a result, the correlation effect becomes more significant than that in the model constructed by the LDA-based downfolding. Furthermore, the Mott-Hubbard type character is enhanced in the GWA-based effective model, because the charge-transfer energy increases more rapidly compared to the increase in the interaction parameters.