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Model of two-dimensional electron gas formation at ferroelectric interfaces

Abstract: The formation of a two-dimensional electron gas at oxide interfaces as a consequence of polar discontinuities has generated an enormous amount of activity due to the variety of interesting effects it gives rise to. Here, we study under what circumstances similar processes can also take place underneath ferroelectric thin films. We use a simple Landau model to demonstrate that in the absence of extrinsic screening mechanisms, a monodomain phase can be stabilized in ferroelectric films by means of an electronic reconstruction. Unlike in the LaAlO3/SrTiO3 heterostructure, the emergence with thickness of the free charge at the interface is discontinuous. This prediction is confirmed by performing first-principles simulations of free-standing slabs of PbTiO3. The model is also used to predict the response of the system to an applied electric field, demonstrating that the two-dimensional electron gas can be switched on and off discontinuously and in a nonvolatile fashion. Furthermore, the reversal of the polarization can be used to switch between a two-dimensional electron gas and a two-dimensional hole gas, which should, in principle, have very different transport properties. We discuss the possible formation of polarization domains and how such configuration competes with the spontaneous accumulation of free charge at the interfaces.

 Fuente: Physical Review B, 2015, 92(3), 035438

 Editorial: American Physical Society

 Fecha de publicación: 01/07/2015

 Nº de páginas: 17

 Tipo de publicación: Artículo de Revista

 DOI: 10.1103/PhysRevB.92.035438

 ISSN: 1098-0121,1550-235X,2469-9950,2469-9969

 Proyecto español: FIS2012-37549-C05

 Url de la publicación: http://dx.doi.org/10.1103/PhysRevB.92.035438

Autoría

BRISTOWE, N.C.

YIN, B.

SHIRASAWA, R.

GHOSEZ, PHILIPPE

LITTLEWOOD, P.B.

ARTACHO, EMILIO