First-principles study of point defects in LiGaO2

TL;DR

This study uses hybrid functional calculations to analyze native point defects in LiGaO2, revealing defect formation energies, dominant defects, and electronic properties, which explain its insulating behavior.

Contribution

It provides the first detailed first-principles analysis of point defects in LiGaO2, highlighting defect energetics and electronic structure.

Findings

Ga_Li^2+ is the lowest energy donor defect

Carrier concentrations are negligible due to Fermi level pinning

V_Ga has high formation energy under all conditions

Abstract

The native point defects are studied in LiGaO2 using hybrid functional calculations. We find that the relative energy of formation of the cation vacancies and the cation antisite defects depends strongly on the chemical potential conditions. The lowest energy defect is found to be the Ga_Li^2+ donor. It is compensated mostly by V_Li^-1and in part by Li_Ga^-2 in the more Li-rich conditions. The equilibrium carrier concentrations are found to be negligible because the Fermi level is pinned deep in the gap and this is consistent with insulating behavior in pure LiGaO2. The V_Ga has high energy under all reasonable conditions. Both the Ga_Li and the V_O are found to be negative U centers with deep 2+/0 transition levels.