Evolution of the electronic structure of SrTiO$_3$/GdTiO$_3$ heterostructures with layer thickness

ORAL

Abstract

A two-dimensional electron gas (2DEG), with density of 3e14cm$^{-2}$ (0.5 electrons per interface unit cell), has been observed at the SrTiO$_3$/GdTiO$_3$ interface, with potential applications in electronic devices [P. Moetakef, T.A. Cain, D.G. Ouellette, J.Y. Zhang, D.O. Klenov, A. Janotti, C.G. Van de Walle, S. Rajan, S.J. Allen, and S. Stemmer, Appl. Phys. Lett. 99, 232116 (2011)]. Yet, basic properties of the 2DEG is still poorly understood, in particular the variation of the electrical conductivity with the SrTiO$_3$ layer thickness. We performed density functional calculations with a hybrid functional to study the electronic structure of SrTiO$_3$/GdTiO$_3$ superlattices. We address the insulator to metal transition as a function of layer thickness, analyzing the effects of quantum confinement, charge ordering, and lattice distortions. Work supported by NSF and ARO.

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Authors

  • Lars Bjaalie

    University of California, Santa Barbara

  • Anderson Janotti

    University of California, Santa Barbara, University of California Santa Barbara, Univ of California - Santa Barbara

  • Chris Van de Walle

    University of California, Santa Barbara, University of California Santa Barbara, Univ of California - Santa Barbara, Matrials Department, University of California, Santa Barabara, Materials Department, University of California, Santa Barbara, California 93106-5050