Tailoring light holes in β−Ga2O3 via anion-anion antibonding coupling

A significant limitation of wide-band-gap materials is their low hole mobility related to localized holes with heavy effective masses (mh*). We identify in low-symmetric wide-band-gap compounds an anion-anion antibonding coupling (AAAC) effect as the intrinsic factor behind hole localization, which explains the extremely heavy mh* and self-trapped hole (STH) formation observed in gallium oxide (β−Ga2O3). We propose a design principle for achieving light holes by manipulating AAAC, demonstrating that specific strain conditions can reduce mh* in β−Ga2O3 along c* from 4.77 m0 to 0.38 m0, making it comparable to the electron mass (0.28 m0) while also slightly suppressing the formation of self-trapped holes, evidenced by the reduction in the formation energy of hole polarons from −0.57 to −0.45 eV under tensile strain. The light holes show significant anisotropy, potentially enabling two-dimensional transport in bulk material. This study provides a fundamental understanding of hole mass enhancement and STH formation in novel wide-band-gap materials and suggests new pathways for engineering hole mobilities. locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon Physics Subject Headings (PhySH)Electrical conductivityElectronic structurePolaronsSemiconductorsDensity functional theory