Dresden 2017 – scientific programme
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DS: Fachverband Dünne Schichten
DS 28: Focussed Session: Oxide Semiconductors for Novel Devices I
DS 28.4: Talk
Wednesday, March 22, 2017, 10:30–10:45, CHE 89
Ab-initio lattice dynamics of Ga2O3 polymorphs with an emphasis on polar phonon modes — •Rut Waldenfels, Dmitrii Nabok, Pasquale Pavone, and Claudia Draxl — Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, Germany
Gallium oxide is a promising material for novel opto-electronic devices, due to its large band gap and its remarkable high carrier mobilities. Understanding electron-phonon interactions and in particular polaronic effects is essential for describing transport properties in polar materials. In this work, we perform a comparative study of the lattice dynamics of the two most stable polymorphs of Ga2O3, the α and β phase, using density-functional theory. We include non-analytical contributions to the dynamical matrix which allow for the full description of polar phonon modes. For these modes, we calculate the dependence of frequencies and eigenvectors on the wave-vector direction. We investigate which modes have the strongest impact on the electronic structure by calculating mode effective charges and average long-range coupling constants.