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arXiv · 1106.4205

Tuning the two-dimensional electron gas at the LaAlO3/SrTiO3(001) interface by metallic contacts

V. G. Ruiz López·R. Arras·W. E. Pickett·R. Pentcheva
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Abstract

First principles calculations reveal that adding a metallic overlayer on LaAlO3/SrTiO3(001) eliminates the electric field within the polar LaAlO3 film and thus suppresses the thickness-dependent insulator-to-metal transition observed in uncovered films. Independent of the LaAlO3 thickness both the surface and the interface are metallic, with an enhanced interface carrier density relative to LaAlO3/SrTiO3(001) after the metallization transition. Moreover, a monolayer thick metallic Ti-contact exhibits a finite magnetic moment and for a thin SrTiO3-substrate induces a spin-polarized 2D electron gas at the n-type interface due to confinement effects. A diagram of band alignment in M/LaAlO3/SrTiO3(001) and Schottky barriers for M=Ti, Al, and Pt are provided.

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V. G. Ruiz López, R. Arras, W. E. Pickett, R. Pentcheva. 2011-06-21. Tuning the two-dimensional electron gas at the LaAlO3/SrTiO3(001) interface by metallic contacts. https://doi.org/10.1103/physrevb.85.125404

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