High Field Magnetoresistance Measurements on the Surface States of Samarium Hexaboride using Corbino Structures

ORAL

Abstract

The recent conjecture of a topologically-protected surface state in SmB$_{6}$ and the verification of robust surface conduction below 4 K have led to a large effort to understand the surface states. Extracting carrier density and charge mobility of these states via Hall measurements is complicated because current can flow on all surfaces of a topological insulator, each of which can have different transport characteristics. We study magnetotransport of SmB$_{6}$ surfaces up to 45 T using a Corbino geometry that is sensitive to individual surfaces. The Corbino allows us to measure conductivity, $\sigma_{xx}$, in both parallel and perpendicular magnetic fields. In the parallel geometry both (110) and (100) samples show a strong negative magnetoresistance. We extracted information about the carrier mobility from the ratio of the perpendicular and parallel magnetoresistance traces. The (110) surface had the highest carrier mobility of 122 cm$^{2}$/Vs with a carrier density of $2.5\times10^{13}$ cm$^{-2}$. The conduction on both polar (100) and non-polar (110) surfaces strongly indicates that the conduction must have a non-polarity-driven origin.

*Performed in part at the National High Magnetic Field Laboratory and the Lurie Nanofabrication Facility. Funded by NSF grant \#DMR-1006500.

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Authors

  • Steven Wolgast

    • Randall Laboratory of Physics, University of Michigan
    • Dept. of Physics, University of Michigan

  • Yun Suk Eo

    • Randall Laboratory of Physics, University of Michigan
    • Dept. of Physics, University of Michigan

  • Gang Li

    • Univ of Michigan - Ann Arbor
    • University of Michigan
    • Univ. of Michigan
    • Randall Laboratory of Physics, University of Michigan
    • Dept. of Physics, University of Michigan
    • University of Michigan, Ann Arbor

  • Ziji Xiang

    • Dept. of Physics, University of Michigan

  • Colin Tinsman

    • Dept. of Physics, University of Michigan

  • Tomoya Asaba

    • Dept. of Physics, University of Michigan

  • Benjamin Lawson

    • Dept. of Physics, University of Michigan

  • Fan Yu

    • Dept. of Physics, University of Michigan

  • J.W. Allen

    • Univ of Michigan - Ann Arbor
    • Randall Laboratory of Physics, University of Michigan
    • Dept. of Physics, University of Michigan

  • Kai Sun

    • Randall Laboratory of Physics, University of Michigan
    • University of Michigan, Ann Arbor
    • University of Michigan
    • Univ of Michigan - Ann Arbor
    • Dept. of Physics, University of Michigan

  • Lu Li

    • Univ of Michigan - Ann Arbor
    • University of Michigan
    • Randall Laboratory of Physics, University of Michigan
    • Dept. of Physics, University of Michigan
    • University of Michigan, Ann Arbor

  • Cagliyan Kurdak

    • Randall Laboratory of Physics, University of Michigan
    • Dept. of Physics, University of Michigan

  • Dae-Jeong Kim

    • Dept. of Physics and Astronomy, University of California, Irvine

  • Zachary Fisk

    • Dept. of Physics and Astronomy, University of California, Irvine