Intrinsic origin of the two-dimensional electron gas at polar oxide interfaces

Source: arXiv

ABSTRACT The predictions of the polar catastrophe scenario to explain the occurrence
of a metallic interface in heterostructures of the solid
solution(LaAlO$_3$)$_{x}$(SrTiO$_3$)$_{1-x}$ (LASTO:x) grown on (001) SrTiO$_3$
were investigated as a function of film thickness and $x$. The films are
insulating for the thinnest layers, but above a critical thickness, $t_c$, the
interface exhibits a constant finite conductivity which depends in a
predictable manner on $x$. It is shown that $t_c$ scales with the strength of
the built-in electric field of the polar material, and is immediately
understandable in terms of an electronic reconstruction at the nonpolar-polar
interface. These results thus conclusively identify the polar-catastrophe model
as the intrinsic origin of the doping at this polar oxide interface.

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    ABSTRACT: We review the recent developments in the electric field control of magnetism in multiferroic heterostructures, which consist of heterogeneous materials systems where a magnetoelectric coupling is engineered between magnetic and ferroelectric components. The magnetoelectric coupling in these composite systems is interfacial in origin, and can arise from elastic strain, charge, and exchange bias interactions, with different characteristic responses and functionalities. Moreover, charge transport phenomena in multiferroic heterostructures, where both magnetic and ferroelectric order parameters are used to control charge transport, suggest new possibilities to control the conduction paths of the electron spin, with potential for device applications.
    Journal of Physics Condensed Matter 07/2012; 24(33):333201. · 2.22 Impact Factor

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