Investigating Stable Low-Energy Gallium Oxide (Ga2O3) Polytypes: Insights into Electronic and Optical Properties from First Principles

Arthi Devamanoharan; Vishnukanthan Venkatachalapathy; Vasu Veerapandy; Ponniah Vajeeston

doi:10.1021/acsomega.3c10192

Investigating Stable Low-Energy Gallium Oxide (Ga₂O₃) Polytypes: Insights into Electronic and Optical Properties from First Principles

ACS Omega. 2024 Mar 26;9(14):16207-16220. doi: 10.1021/acsomega.3c10192. eCollection 2024 Apr 9.

Authors

Arthi Devamanoharan¹, Vishnukanthan Venkatachalapathy^{2

3}, Vasu Veerapandy¹, Ponniah Vajeeston⁴

Affiliations

¹ School of Physics, Madurai Kamaraj University, Madurai 625021, India.
² Department of Physics/Centre for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1048 Blindern, Oslo NO-0316, Norway.
³ Department of Materials Science, National Research Nuclear University "MEPhI", 31 Kashirskoe Sh., Moscow 115409, Russian Federation.
⁴ Center for Materials Science and Nanotechnology, University of Oslo, Oslo 0371, Norway.

Abstract

This study provides a comprehensive analysis of the electronic and optical properties of low-energy gallium oxide (Ga₂O₃) polytypes not considered earlier. Among these polytypes, the monoclinic structure (β-Ga₂O₃) holds significant relevance for both research and practical applications due to its superior stability under typical conditions. The primary aim of this research is to identify new and stable Ga₂O₃ polytypes that may exist under zero-temperature and zero-pressure conditions. To achieve this objective, we employ the VASP code to investigate electrical and optical properties, as well as stability assessments. Additionally, we examine phonon and thermal properties, including heat capacity, for all polytypes. This study also encompasses the computation of full elastic tensors and elastic moduli for all polytypes at 0 K, with Poisson's and Pugh's ratios confirming their ductile nature. Furthermore, we present the first ever report on the Raman- and infrared (IR)-active modes of these stable Ga₂O₃ polytypes. Our findings reveal that these mechanically and dynamically stable Ga₂O₃ polytypes exhibit semiconductive properties, as evidenced by electronic band structure investigations. This research offers valuable insights into the optical characteristics of Ga₂O₃ polytypes with potential applications spanning various fields.