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HL: Fachverband Halbleiterphysik

HL 52: Focus Session: Functional Metal Oxides for Novel Applications and Devices I (joint session HL/DS)

HL 52.2: Vortrag

Mittwoch, 18. März 2020, 15:30–15:45, POT 81

Two-dimensional electron (hole) gas in BaSnO₃/LaInO₃ heterostructures: A first-principles study — •Wahib Aggoune, Dmitrii Nabok, and Claudia Draxl — Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, Berlin, Germany

We investigate the structural and electronic properties of heterostructures formed by the nonpolar BaSnO₃ (BSO) and polar LaInO₃ (LIO) perovskites, employing density functional theory. Focusing on the impact of thickness and surface termination of the LIO side, we analyze the electronic properties of the interface. For the stoichiometric LIO film, an internal electric field is induced due to the different terminations of its two sides. Increasing the LIO thickness, this field causes an upward shift of the valence band maximum (VBM). Reaching a thickness of 6 LIO unit cells, the VBM crosses the Fermi level, leading to partial occupation of the conduction band minimum (CBM). Consequently, a two-dimensional electron gas (2DEG) forms at the BSO side of the interface, confined within three unit cells. A high electron mobility is expected due to the s-character of the CBM. The corresponding hole gas (2DHG) forms at the LIO side, confined within one unit cell. As a result, this combination gives rise to the formation of a conducting interface starting from the insulating BSO and LIO components. We also present its results for interfaces with non-stoichiometric LIO. Depending on the surface termination, either a 2DEG or a 2DHG forms at the interface. In this case, the 2D charge confinement is mainly attributed to the spontaneous polarization induced at the interface.