Itinerant electron ferromagnetism at GdTiO$_{3}$/SrTiO$_{3}$ heterostructure

ORAL

Abstract

Interfaces between perovskite oxides have known to support conducting two dimensional electron gases (2DEGs) even when the parent materials are insulators. When one of the insulating parent materials is magnetic, the magnetism is inherited by the 2DEG. We will discuss the itinerant-electron magnetic 2DEGs which occur at GdTiO$_{3}$/SrTiO$_{3}$ interfaces in which the 2DEG resides on the otherwise non-magnetic SrTiO$_{3}$ side of the interface. Experimental studies [1,2] have shown magnetoresistance effects that are characteristic of itinerant electron ferromagnets, but the origin of the magnetic coupling is still not resolved. In this study, we propose that the ferromagnetic state of the 2DEG originates from exchange coupling between 2DEG electrons and electrons localized on GdTiO$_{3}$ Ti sites near the interface. We develop a tight binding model that accounts for this coupling and its relation to structural distortion of GdTiO$_{3}$ near the interface, and address its influence on 2DEG properties. \\[4pt] [1] P. Moetakef, J. R. Williams, D. G. Ouellette, A. P. Kajdos, D. Goldhaber-Gordon, S. J. Allen, and S. Stemmer, Phys. Rev. X 2, 021014 (2012). \\[0pt] [2] C. A. Jackson and S. Stemmer, arXiv:1311.0337

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Authors

  • Ming Xie

    The University of Texas at Austin

  • Allan MacDonald

    The University of Texas at Austin, Department of Physics, University of Texas at Austin, Austin, Texas 78712-1081, USA, Department of Physics, The University of Texas at Austin, Austin, TX, 78712, Department of Physics, University of Texas at Austin, University of Texas at Austin, University of Texas at Austin, Austin, Texas 78712, USA, UT Austin, Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA