Dresden 2020 – scientific programme
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DS: Fachverband Dünne Schichten
DS 42: Focus Session: Functional Metal Oxides for Novel Applications and Devices III (joint session HL/DS)
DS 42.1: Talk
Thursday, March 19, 2020, 15:00–15:15, POT 81
Ab-initio investigation of first-order Raman scattering in gallium oxide — •Rouven Koch, Pasquale Pavone, Dmitrii Nabok, and Claudia Draxl — Humboldt-Universität zu Berlin, Physics Department and IRIS Adlershof, Germany
In this work, we investigate the Raman tensors and first-order spectra of the β and α phase of Ga2O3
by means of first-principles calculations using the ab-initio methodology implemented in the software package
T1lmttbnexciting [1]. We start from the determination of the equilibrium crystal structure of both polymorphs.
Then, we explore the lattice dynamics of the two phases, paying special attention to the characterization of the phonons
at the Γ point. The peculiar properties of the polar phonon modes of the β phase are addressed, including
the LO-TO splitting and reflectivity spectra. Then, we compute the frequency-dependent dielectric tensors within the
random-phase approximation. The lattice-dynamical properties and the dielectric tensors are used for the calculation
of the Raman spectra in different polarizations. The obtained polarized Raman spectra for α- and β-Ga2O3
are compared to available data in the literature [2]. Our results highlight the fact that excitonic effects do not play
a significant role on off-resonance Raman spectra. The overall good agreement with the experiments indicates the accuracy
of the approximations used in this calculation.
[1] A. Gulans et al., J. Phys.: Condens. Matter 26 (2014) 363202;
[2] C. Kranert et al., Scientific Reports 6 (2016) 35964.