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Visualizing the Impact of Quenched Disorder on Electron Wigner Solids

ORAL

Abstract

Understanding electronic systems that have both strong electron-electron interactions and electron-disorder interactions is challenging. In a disorder-free bare 2D electronic system it is well known that electrons form a Wigner crystal (WC) when the ratio (rs) between electron-electron Coulomb repulsion energy and electron kinetic energy exceeds ~37. In real materials, however, defects and impurities are always present and can alter electronic behavior compared to the disorder-free limit. For example, it has been predicted that quenched disorder can distort the triangular lattice of a pure 2D WC and reduce the critical rs​ at which melting occurs due to pinning effects. Real-space experimental characterization of the effects of quenched disorder on WCs, however, remains limited. Here I will present results from our recent scanning tunneling microscopy (STM) study of disordered electron WCs in gate-tunable bilayer MoSe2 devices. We have observed that different MoSe2​ atomic defects provide disorder potentials that can be characterized as either repulsive or attractive, as well as either long-range or short-range. The impact of these different types of disorder potentials on the wavefunction and quantum melting behavior of disordered electron WCs will be discussed.

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Presenters

  • Zhehao Ge

    University of California, Berkeley

Authors

  • Zhehao Ge

    University of California, Berkeley

  • Zehao He

    University of California, Berkeley

  • Qize Li

    University of California, Berkeley

  • Ziyu Xiang

    University of California, Berkeley

  • Jianghan Xiao

    University of California, Berkeley

  • Salman A Kahn

    Lawrence Berkeley National Laboratory

  • Wenjie Zhou

    University of California, Berkeley

  • Mit H. Naik

    University of California, Berkeley, University of Texas at Austin

  • Renee Sailus

    Arizona State University

  • Rounak Banerjee

    Arizona State University

  • Takashi Taniguchi

    National Institute for Materials Science, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, International Center for Materials Nanoarchitectonics, National Institute of Material Science, Tsukuba, Japan, Advanced Materials Laboratory, National Institute for Materials Science

  • Kenji Watanabe

    National Institute for Materials Science, NIMS, Research Center for Functional Materials, National Institute for Materials Science, Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, Research Center for Functional Materials, National Institute of Material Science, Tsukuba, Japan, National Institute of Materials Science, Advanced Materials Laboratory, National Institute for Materials Science

  • Sefaattin Tongay

    Arizona State University

  • Steven G Louie

    University of California, Berkeley, University of California, Berkeley and Lawrence Berkeley National Lab, University of California, Berkeley and Lawrence Berkeley National Laboratory, Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Department of Physics, University of California at Berkeley, Berkeley, CA, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

  • feng wang

    University of California, Berkeley

  • Michael F Crommie

    University of California, Berkeley