Electronic properties and superconductivity in infinite-layer nickelate composts

TL;DR

This study explores the electronic structure and superconductivity in nickelate compounds using advanced theoretical methods, revealing how pressure, doping, and inter-band interactions influence their electronic properties and superconducting phases.

Contribution

It introduces a comprehensive analysis combining P-DFT and multi-band BCS theory to understand superconductivity in nickelates, highlighting the effects of pressure, doping, and inter-band coupling.

Findings

Pressure redistributes band structures and destroys van Hove singularities near Fermi level.

Doping at x=0.5 leads to a flat band in the electronic structure.

Inter-band coupling is crucial for superconductivity in nickelates.

Abstract

In this paper we investigate the electronic and superconducting properties in nickelate compounds of NiO2 through Perturbative Density Functional Theory (P-DFT) and multi-band BCS theory. We consider three different cases of study (i) the crystalline structure composed by two layers of NiO2, with a central single atom of Nd, Yb or Pr, which is subjected to mechanical compression and tension forces (pressure), (ii) the crystalline structure composed by three layers of NiO2 with central atom pairs of Nd-Nd, Nd-Sr or Sr-Sr, where the level doping x correspond to change between Nd/Sr and (iii) through multi-band theory we study the behaviour in a single-layer Nd1-xSrxNiO2} when $x$=0.5 through gaps $\Delta_{\chi,\textbf{p}}$, with $\chi$ (number of band or orbitals), only with the presence of inter-band coupling $V_{\chi\chi'}$. As results, for (i) and (ii) we present the electronic measures of the electronic band structures \textit{e-DOS}, \textit{p-DOS}. In (i) we show that under pressure there are a re-distribution of the band structures for \textit{e-DOS}, \textit{p-DOS}, allowing the destruction of van-\textit{Hove} near Fermi level $E_{F}$, thus in (ii) we show the presence of a single flat band when the doping level is $x$=0.5 and for (iii) the inter-band coupling between orbitals play a key role in the construction of a superconducting phase in nickelates compounds.