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Two-dimensional electron gas at the PbTi O3/SrTi O3 interface: an ab initio study

Abstract: In the polar catastrophe scenario, polar discontinuity accounts for the driving force of the formation of a two-dimensional electron gas (2DEG) at the interface between polar and nonpolar insulators. In this paper, we substitute the usual, nonferroelectric, polar material with a ferroelectric thin film and use the ferroelectric polarization as the source for polar discontinuity. We use ab initio simulations to systematically investigate the stability, formation, and properties of the two-dimensional free-carrier gases formed in PbTiO3/SrTiO3 heterostructures under realistic mechanical and electrical boundary conditions. Above a critical thickness, the ferroelectric layers can be stabilized in the out-of-plane monodomain configuration due to the electrostatic screening provided by the free carriers. Our simulations also predict that the system can be switched between three stable configurations (polarization up, down, or zero), allowing the nonvolatile manipulation of the free-charge density and sign at the interface. Furthermore, the link between ferroelectric polarization and free-charge density demonstrated by our analysis constitutes compelling support for the polar catastrophe model that is used to rationalize the formation of 2DEG at oxide interfaces.

Otras publicaciones de la misma revista o congreso con autores/as de la Universidad de Cantabria

 Fuente: Physical Review B, 2015, 92(11), 115406

Editorial: American Physical Society

 Año de publicación: 2015

Nº de páginas: 11

Tipo de publicación: Artículo de Revista

 DOI: 10.1103/PhysRevB.92.115406

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.92.115406