Electronic structure of silver-deficient hexagonal AgB$_2$

TL;DR

This study investigates the electronic structure and stability of silver-deficient hexagonal AgB₂ using density functional theory, revealing that vacancies have minimal impact on the density of states at the Fermi level and suggesting a wide homogeneity region for silver vacancies.

Contribution

It provides the first detailed computational analysis of silver vacancies in AgB₂, highlighting their effect on electronic properties and stability.

Findings

Density of states at Fermi level remains nearly constant with up to 25% vacancies.

Formation energy of silver vacancies is the lowest among 4d metal diborides.

Wide homogeneity region for silver vacancies in AgB₂ is possible.

Abstract

Electronic structure and cohesive properties of metastable hexagonal AgB_{2} and silver-deficient borides Ag_{0.875}B_{2} and Ag_{0.750}B_{2} were investigated by means of the projected augmented wave method in the framework of the density functional theory (VASP package). We found that the density of states at the Fermi level for nonstoichiometric diborides is almost constant within a range of vacancy content up to 25%. The formation energy of metal vacancies in silver diboride is the least among all 4d metal diborides, i.e. for AgB_{2} is possible to expect the wide homogeneity region.