Exceptionally Long-ranged Lattice Relaxation in Oxygen-deficient Ta2O5

TL;DR

This study reveals that oxygen vacancies in Ta2O5 cause long-range lattice relaxation effects extending over 18 Å, significantly impacting the material's electronic properties and vacancy formation energy.

Contribution

It provides first-principles evidence of exceptionally long-ranged lattice relaxation in oxygen-deficient Ta2O5, explaining the phenomenon through Hellmann-Feynman forces and potential energy surface analysis.

Findings

Lattice relaxation extends beyond 18 Å from vacancy site

Significant effects on vacancy formation energy and electronic structure

Long-range relaxation explained by force and energy surface analysis

Abstract

The lattice relaxation in oxygen-deficient Ta2O5 is investigated using first-principles calculations. The presence of a charge-neutral oxygen vacancy can result in a long-ranged lattice relaxation which extends beyond 18 {\AA} from the vacancy site. The lattice relaxation has significant effects on the vacancy formation energy as well as the electronic structures. The long-ranged behavior of the lattice relaxation is explained in terms of the Hellmann-Feynman forces and the potential energy surface related to the variation of Ta-O bond lengths.