First-principles study of Janus GaInXO (X = S, Se, Te)

Recently, considerable interest in Janus 2D materials has sparked various research investigations. Using density functional theory calculations, we study the atomic and electronic structure of six two-dimensional Janus GaInXO (X = S, Se, Te) materials to investigate their structural, vibrational, and piezoelectric properties. Their structural stability is evaluated through phonon calculations and molecular dynamics (MD) simulations at room temperature. The results show that OGaInTe is unstable, which is examined through crystal orbital Hamilton population (COHP) analysis. For the stable materials, Raman spectra are calculated for comparison with synthesis results. Furthermore, band-structure calculations with spin–orbit coupling are performed for SGaInO, SeGaInO, and OGaInS with bandgaps to evaluate their potential applications. Finally, calculations for piezoelectric properties reveal that OGaInSe exhibits the highest piezoelectric strain coefficient, confirming its strong potential as a piezoelectric device.