Vacancy defect positron lifetimes in strontium titanate

TL;DR

This study investigates vacancy defects in strontium titanate using positron lifetime spectroscopy, revealing defect types and lifetimes in variously doped and irradiated samples through first-principles calculations.

Contribution

It combines experimental positron lifetime measurements with first-principles calculations to identify vacancy defect types and their lifetimes in SrTiO3.

Findings

Undoped crystals show Ti vacancy related defect lifetimes.

Nb doping and irradiation affect vacancy defect populations.

First-principles calculations match experimental defect lifetimes.

Abstract

The results of positron annihilation lifetime spectroscopy measurements on undoped, electron irradiated, and Nb doped SrTiO3 single crystals are reported. Perfect lattice and vacancy defect positron lifetimes were calculated using two different first-principles schemes. The Sr vacancy defect related positron lifetime was obtained from measurements on Nb doped, electron irradiated, and vacuum annealed samples. Undoped crystals showed a defect lifetime component dominated by trapping to Ti vacancy related defects.