LaAlO₃ - Buckling under pressure to hand over the charges

In this paper, we report on the change in the atomic structure of the conducting interface between the insulators LaAlO₃ and SrTiO₃ as a function of the LaAlO₃ layer thickness. We discovered that the atoms at the interface buckle in an attempt to counteract the internal electric field produced when these two insulators touch one another. Despite the partial neutralizing effect of the buckling, the electrical potential becomes sufficiently high above a critical thickness to pull electrons out of the LaAlO₃ and provide the conducting layer. The electric field then collapses and the buckling is suppressed. These findings, made possible using x-ray scattering techniques capable of identifying atomic positions down to one millionth of one millionth of a meter, explain at a structural level the discoveries of the conductivity at the interface in 2004 and the need for a minimum LaAlO₃ thickness to induce it, in 2006. This phenomenon may have important technological applications in future nanoscale electronics based on metal-oxides."

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