2D Small Hole Polarons in Ga<sub>2</sub>O<sub>3</sub>.

Peelaers, Hartwin; Varley, Joel B; Van de Walle, Chris G · Nano Lett · 2026

basic_science · Level V

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Abstract

It is well known that holes in oxides such as Ga<sub>2</sub>O<sub>3</sub> localize and distort the lattice, forming small polarons. Here we explore the formation of polarons in (100) Ga<sub>2</sub>O<sub>3</sub> nanolayers, which have been experimentally demonstrated. Using density functional theory at the hybrid functional level, we show that polarons can localize on oxygen atoms, with two of the symmetrically inequivalent (3-fold coordinated) O sites leading to stable polarons and the 4-fold coordinated position being metastable. This metastable polaron requires the breaking of a Ga-O bond and leads to a large displacement of a Ga atom. The combination of such a large displacement and a 2D layer should allow for experimental observation by using high-resolution transmission electron microscopy.