Magnetotransport in topological insulator-ferromagnetic insulator heterostructure devices

ORAL

Abstract

Topological surface states modified by the presence of magnetism are predicted to play host to a number of exotic phenomena and are of great fundamental as well as applied interest. Interfacing topological insulators with magnetic insulators offers a unique opportunity to access these effects by transport, without affecting the bulk band structure. We demonstrate the integration of MBE grown thin films of Bi$_2$Se$_3$ with the insulating ferromagnet GdN. SQUID measurements of the hetero-structure reveal an in-plane easy axis with a ferromagnetic Curie temperature $T_c$ $\sim$ 13 K. The fabrication of hall devices with bare and GdN-capped channels enables direct comparison of magneto-transport properties. While the bare channel displays conventional weak anti-localization (WAL), the capped channel reveals a weakened WAL and a superimposed negative magnetoresistance (MR) associated with weak localization. These observations are discussed in the context of gap-opening in the Dirac surface state. Finally, we discuss the observation of hysteresis in the MR of the capped channel below 2 K.

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Authors

  • Abhinav Kandala

    Penn State University

  • Anthony Richardella

    Department of Physics, Pennsylvania State University, University Park, PA 16802, USA, Department of Physics, Penn State University, Dept. of Physics and Center for Nanoscale Science, Penn State University, University Park PA 16802, Penn State University

  • David Rench

    Penn State University

  • Duming Zhang

    Penn State University

  • Thomas Flanagan

    Penn State University

  • Nitin Samarth

    The Pennsylvania State University, Department of Physics, Pennsylvania State University, University Park, PA 16802, USA, Department of Physics, Penn State University, Pennsylvania State University, Dept. of Physics and Center for Nanoscale Science, Penn State University, University Park PA 16802, Penn State University