Electronic band structure of novel tetragonal BiOCuS as a parent phase for novel layered superconductors

TL;DR

This study uses first-principles calculations to analyze the electronic structure of the newly synthesized tetragonal BiOCuS, revealing its potential as a semiconductor parent phase for layered superconductors upon doping.

Contribution

First detailed electronic structure analysis of BiOCuS, showing its semiconducting nature and potential for superconductivity through doping.

Findings

BiOCuS is an ionic semiconductor with a 0.48 eV indirect band gap.

Hole doping induces conductivity in [CuS] blocks near the Fermi level.

Fermi surface becomes quasi-two-dimensional after doping, similar to FeAs superconductors.

Abstract

Very recently, the tetragonal BiOCuS was synthesized and declared as a new superconducting system with Fe-oxypnictide - related structure. Here, based on first-principle FLAPW-GGA calculations, the structural parameters, electronic bands picture, density of states and electron density distribution for BiOCuS are investigated for the first time. Our results show that, as distinct from related metallic-like FeAs systems, BiOCuS phase behaves as an ionic semiconductor with the calculated indirect band gap at about 0.48 eV. The superconductivity for BiOCuS may be achieved exclusively by doping of this phase. Our preliminary results demonstrate that as a result of hole doping, the [CuS] blocks become conducting owing to mixed Cu 3d + S 3p bands located near the Fermi level. For the hole doped BiOCuS the Fermi surface adopts a quasi-two-dimensional character, similarly to FeAs SCs.