Dresden 2017 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 55: Electronic-Structure Theory: New Concepts and Developments in Density Functional Theory and Beyond - IV
HL 55.6: Talk
Wednesday, March 22, 2017, 12:00–12:15, GER 38
Conditions for formation of two-dimensional electron gas at the LaFeO3/SrTiO3 — •Igor Maznichenko1, Sergey Ostanin1, Arthur Ernst2, Ingrid Mertig1,2, Katayoon Mohseni2, Holger L. Meyerheim2, Eberhard K.U. Gross2, Pengfa Xu3, Wei Han3, Philip M. Rice3, Jaewoo Jeong3, Mahesh G. Samant3, and Stuart S.P. Parkin2,3 — 1Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany — 2Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany — 3IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
The formation of a conducting two dimensional electron gas (2DEG) at the interface between two insulating oxide layers was explained theoretically for atomically and chemically abrupt interfaces via polar discontinuity.
Here we show that a 2DEG is formed at the interface between thin layers of lanthanum ferrite, LaFeO3 (LFO), that are more than 3 unit cells thick, when grown epitaxially on SrTiO3 (STO) (001). The interface property highly depends on the surface property of TiO2 terminated STO. The interface is conducting if the STO is not annealed in an oxygen environment prior to the LFO growth, while insulating if the STO is annealed.
First principles calculations reveal that a 2DEG should be realized for an ideal interface but that modest chemical intermixing suppresses it. These calculations also show that the presence of oxygen vacancies supports 2DEG formation due to electronic doping.