Electronic properties and Fermi surface for new Fe-free layered superconductor BaTi2Bi2O from first principles

TL;DR

This paper investigates the electronic structure and Fermi surface of the newly discovered Fe-free superconductor BaTi2Bi2O using first-principles calculations, providing insights into its high transition temperature.

Contribution

First detailed electronic and Fermi surface analysis of BaTi2Bi2O, highlighting factors behind its higher superconducting transition temperature.

Findings

Electronic bands and Fermi surface topology characterized.

Bonding is a mixture of metallic, covalent, and ionic types.

Structural and electronic factors linked to higher Tc discussed.

Abstract

Very recently, as an important step in the development of layered Fe-free pnictide-oxide superconductors, the new phase BaTi2Bi2O was discovered which has the highest TC (about 4.6 K) among all related non-doped systems. In this Letter, we report for the first time the electronic bands, Fermi surface topology, total and partial densities of electronic states for BaTi2Bi2O obtained by means of the first-principles FLAPW-GGA calculations. The inter-atomic bonding picture is described as a high-anisotropic mixture of metallic, covalent, and ionic contributions. Besides, the structural and electronic factors, which can be responsible for the increased transition temperature for BaTi2Bi2O (as compared with related pnictide-oxides BaTi2As2O and BaTi2Sb2O), are discussed.