Tunable spin and valley excitations of correlated insulators in Γ-valley moiré bands

ORAL

Abstract

Moiré superlattices formed from transition metal dichalcogenides (TMDs) have been shown to support a variety of quantum electronic phases that are highly tunable using applied electromagnetic fields. In this talk, I will describe a new approach to engineer and study correlations within Γ-valley moiré bands in twisted double bilayer WSe2. Through a combination of local and global electronic compressibility measurements, we identify charge-ordered phases at multiple integer and fractional moiré band fillings ν. By measuring the magnetic field dependence of their energy gaps and the chemical potential upon doping, we reveal spin-polarized ground states with novel spin polaron quasiparticle excitations. In addition, an applied displacement field allows us to realize a new mechanism of metal-insulator transition at ν = -1 driven by tuning between Γ- and K-valley moiré bands. Together, our results demonstrate control over both the spin and valley character of the correlated ground and excited states in this system.

*Experimental work was primarily supported by NSF-DMR-2103910. B.E.F. acknowledges an Alfred P. Sloan Foundation Fellowship and a Cottrell Scholar Award.

–

Publication: arXiv:2206.10631

Presenters

  • Benjamin Foutty

    • Stanford University

Authors

  • Benjamin Foutty

    • Stanford University

  • Jiachen Yu

    • Stanford University

  • Trithep Devakul

    • MIT

  • Carlos R Kometter

    • Stanford Univ
    • Stanford University

  • Yang Zhang

    • MIT
    • Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
    • Massachusetts Institute of Technology
    • Massachusetts Institute of Technology MIT

  • Kenji Watanabe

    • National Institute for Materials Science
    • Research Center for Functional Materials, National Institute of Materials Science
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, Japan
    • NIMS
    • Research Center for Functional Materials, National Institute for Materials Science
    • National Institute for Materials Science, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
    • NIMS Japan

  • Takashi Taniguchi

    • National Institute for Materials Science
    • Kyoto Univ
    • International Center for Materials Nanoarchitectonics, National Institute of Materials Science
    • Kyoto University
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science
    • National Institute for Materials Science, Japan
    • National Institute For Materials Science
    • NIMS
    • National Institute for Material Science
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
    • NIMS Japan

  • Liang Fu

    • Massachusetts Institute of Technology MIT
    • Massachusetts Institute of Technology

  • Ben Feldman

    • Stanford University
    • Stanford Univ