Dimensionality effect on the charge density wave and superconductivity of molecular beam epitaxy grown monolayer NbSe$_{\mathrm{2}}$

ORAL

Abstract

Transition metal dichalcogenides are ideal compounds to investigate dimensionality effect since the weak coupling between layers enables to study single-layer material which removes interlayer interactions and introduces quantum confinement. We investigate dimensionality effect of NbSe$_{\mathrm{2}}$ in which the bulk phase shows charge density wave (CDW) (T$_{\mathrm{CDW}}=$33 K) and superconductivity (T$_{\mathrm{c}}=$7.2 K). We report electronic band structure of MBE grown monolayer NbSe$_{\mathrm{2}}$ measured by Angel-resolved photoemission spectroscopy compared with bulk. We find the number of bands crossing the Fermi energy reduces from three (bulk) to one (monolayer). Based on the significant suppression of superconducting T$_{\mathrm{c}}=$0.65 K with robust CDW in monolayer NbSe$_{\mathrm{2}}$, our results imply the band remained at the Fermi level in monolayer NbSe$_{\mathrm{2}}$ may play a crucial role in CDW formation and the disappeared bands are possibly in charge of superconductivity.

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Authors

  • Hyejin Ryu

    • Lawrence Berkeley National Lab.
    • Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

  • Yi Zhang

    • Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

  • Zahid Hussain

    • Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

  • Sung-Kwan Mo

    • Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

  • Z.-X. Shen

    • Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, California 94305, USA

  • Miguel M. Ugeda

    • Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA

  • Aaron J. Bradley

    • Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA

  • Seita Onishi

    • Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA

  • Yi Chen

    • Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA

  • Wei Ruan

    • Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA

  • Claudia Ojeda-Aristizabal

    • Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA

  • Mark T. Edmonds

    • Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA

  • Hsin-Zon Tsai

    • Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA

  • Alexander Riss

    • Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA

  • Dunghai Lee

    • Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA

  • Alex Zettl

    • Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA

  • Michael F. Crommie

    • Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA