Structure and transport of topological insulators on epitaxial graphene

ORAL

Abstract

Recent advancements in spintronics have shown that a class of materials, topological insulators (TI), can be used as a spin-current generator or detector. Topological insulators have protected surface states with the electron’s spin locked to its momentum. To access these surface states, (Bi, Sb)$_{2}$Te$_{3}$ can be grown by molecular beam epitaxy to have the Fermi energy near the Dirac point so that transport occurs only through the spin-dependent surface states. Graphene is another 2D material of great interest for spintronics because of its very long spin diffusion length. This is an ideal material to act as a spin channel in devices. The van der Waals nature of the growth exhibited by 2D materials such as (Bi, Sb)$_{2}$Te$_{3}$ and graphene allows heterostructures to be formed despite the large lattice mismatch. We explore the structure and transport of (Bi, Sb)$_{2}$Te$_{3}$ grown on epitaxial graphene on 6H-SiC substrates for spintronic applications.

*This work was supported in part by C-SPIN and LEAST, two of the six centers of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA.

Authors

  • James Kally

    • Dept. of Physics, Penn State Univ.
  • Danielle Reifsnyder-Hickey

    • Dept. of Chemical Engineering and Materials Science, Univ. of Minnesota
    • University of Minnesota
  • Yu-Chuan Lin

    • Dept. of Materials Science and Engineering, Penn State Univ.
  • Anthony Richardella

    • The Pennsylvania State University
    • Dept. of Physics, Penn State Univ.
    • Pennsylvania State university
  • Joon Sue Lee

    • California NanoSystems Institute
    • Dept. of Physics, Penn State Univ.
  • Joshua Robinson

    • Dept.of Materials Science and Engineering, Penn. State Univ.
  • Andre Mkhoyan

    • Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455
    • University of Minnesota
    • Dept. of Chemical Engineering and Materials Science, Univ. of Minnesota
  • Nitin Samarth

    • Pennsylvania State Unversity
    • The Pennsylvania State University
    • Pennsylvania State University
    • Dept. of Physics, Penn State Univ.
    • Dept. of Physics, Penn State University, University Park PA 16802