【Others Papers】Tailoring light holes in β−Ga₂O₃ via anion-anion antibonding coupling

      Researchers from the Nanjing University have published a dissertation titled "Tailoring light holes in β−Ga₂O₃ via anion-anion antibonding coupling" in Physical Review B.

Abstract

      A significant limitation of wide-band-gap materials is their low hole mobility related to localized holes with heavy effective masses (m*_h). 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 m*_h 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 m*_h 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.

DOI：

https://doi.org/10.1103/PhysRevB.110.235208