Two-gap superconductivity and decisive role of rare-earth $d$ electrons in infinite-layer nickelates

Fuente: arXiv
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Main Authors: Li, Zhenglu, Louie, Steven G.
Format: Preprint
Published: 2022
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author Li, Zhenglu
Louie, Steven G.
author_facet Li, Zhenglu
Louie, Steven G.
contents We present a theoretical prediction of a phonon-mediated two-gap superconductivity in infinite-layer nickelates Nd$_{0.8}$Sr$_{0.2}$NiO$_2$ by performing $\textit{ab initio}$ $GW$ and $GW$ perturbation theory calculations. Electron $GW$ self-energy effects significantly alter the characters of the two-band Fermi surface and enhance the electron-phonon coupling, compared with results based on density functional theory. Solutions of the fully $\textbf{k}$-dependent anisotropic Eliashberg equations yield two dominant $s$-wave superconducting gaps - a large gap on a band of rare-earth Nd $d$ and interstitial orbital characters and a small gap on a band of transition-metal Ni $d$ character. Increasing hole doping induces a non-rigid-band response in the electronic structure, leading to a rapid drop of the superconducting $T_c$ in the overdoped regime in agreement with experiments.
format Preprint
id arxiv_https___arxiv_org_abs_2210_12819
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Two-gap superconductivity and decisive role of rare-earth $d$ electrons in infinite-layer nickelates
Li, Zhenglu
Louie, Steven G.
Superconductivity
Materials Science
Strongly Correlated Electrons
We present a theoretical prediction of a phonon-mediated two-gap superconductivity in infinite-layer nickelates Nd$_{0.8}$Sr$_{0.2}$NiO$_2$ by performing $\textit{ab initio}$ $GW$ and $GW$ perturbation theory calculations. Electron $GW$ self-energy effects significantly alter the characters of the two-band Fermi surface and enhance the electron-phonon coupling, compared with results based on density functional theory. Solutions of the fully $\textbf{k}$-dependent anisotropic Eliashberg equations yield two dominant $s$-wave superconducting gaps - a large gap on a band of rare-earth Nd $d$ and interstitial orbital characters and a small gap on a band of transition-metal Ni $d$ character. Increasing hole doping induces a non-rigid-band response in the electronic structure, leading to a rapid drop of the superconducting $T_c$ in the overdoped regime in agreement with experiments.
title Two-gap superconductivity and decisive role of rare-earth $d$ electrons in infinite-layer nickelates
topic Superconductivity
Materials Science
Strongly Correlated Electrons
url https://arxiv.org/abs/2210.12819