Imaging Dirac-Mass Disorder from Magnetic Dopant-Atoms in the Ferromagnetic Topological Insulator Cr$_{x}$(Bi$_{0.1}$Sb$_{0.9}$)$_{2-x}$Te$_{3}$ - Part II

ORAL

Abstract

We present Part II of the spectroscopic imaging - scanning tunneling microscopy (SI-STM) study of ferromagnetic Cr$_{x}$(Bi$_{0.1}$Sb$_{0.9}$)$_{2-x}$Te$_{3}$ single crystals measured at 4.5 K. As Part II we show how both spectroscopic analysis in real and momentum space demonstrate the coincident Dirac mass gap identified. Distribution of gap width, gap center, and gap anisotropy will be discussed. The anticipated relationship $\Delta(r) \propto n(r)$ is confirmed throughout, and exhibits an electron-dopant interaction energy $J^{*}=$145 meV$\cdot$nm$^{2}$. These observations reveal how magnetic dopant atoms actually generate the TI mass gap and that, to achieve the novel physics expected of time-reversal-symmetry breaking TI materials, control of the resulting Dirac-mass gap disorder will be essential.

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Authors

  • Inhee Lee

    • Brookhaven National Laboratory
    • BNL

  • Chung Koo Kim

    • Brookhaven National Laboratory
    • BNL
    • CMPMS Brookhaven National Lab, Cornell University

  • Jinho Lee

    • Seoul National University
    • BNL, SNU

  • Simon Billinge

    • Columbia University
    • BNL, Columbia

  • Ruidan Zhong

    • Brookhaven National Laboratory
    • Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, NY 11973, USA
    • BNL, Stony Brook
    • Brookhaven National Lab

  • John Schneeloch

    • Brookhaven National Laboratory
    • Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, NY 11973, USA
    • Brookhaven Natl Lab
    • BNL, Stony Brook
    • Brookhaven National Lab

  • Tiansheng Liu

    • Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, NY 11973, USA
    • Brookhaven National Laboratory

  • John Tranquada

    • Brookhaven National Laboratory
    • Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, NY 11973, USA
    • Brookhaven Natl Lab
    • BNl

  • Genda Gu

    • Brookhaven National Lab
    • Brookhaven National Laboratory
    • Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, NY 11973, USA
    • Brookhaven Natl Lab
    • BNL
    • Department of Physics, Brookhaven National Laboratory
    • Brookhaven National Lab, Upton, NY
    • University of Colorado at Boulder

  • J.C. Davis

    • Cornell University
    • BNL, Cornell, U of St. Andrews, Kavli Inst. at Cornell
    • Cornell University, CMPMS Brookhaven National Lab, University of St. Andrews, Kavli Institute at Cornell for Nanoscale Science