Predicting the Raman spectra of ferroelectric phases in two-dimensional Ga2O3 monolayer

Abstract

We investigate the vibrational properties and Raman spectra of the two-dimensional Ga₂O₃ monolayer, using density functional theory. Two ferroelectric (FE) phases of the Ga₂O₃ monolayer with wurtzite (WZ) and zinc blende (ZB) structures (FE–WZ and FE–ZB, respectively) are considered. The Raman tensor and angle-dependent Raman intensities of two major Raman peaks (A¹₁ and A²₁) in both FE–WZ (497, and 779 cm⁻¹) and FE–ZB (481, and 772 cm⁻¹) Ga₂O₃ monolayers, are calculated for the polarization of scattered light, parallel and perpendicular to that of the incident light. The characteristics of angle-dependent Raman intensities are analyzed. The average non-resonant Raman spectra of the minor peaks in FE–WZ (E¹) and FE–BZ (E¹ and E²) are compared with those of major peaks A¹₁ and A²₁. These predictions of the Raman spectra of the Ga₂O₃ monolayer may guide the rational design of two-dimensional optical devices.