Control of Giant Topological Magnetic Moment and Valley Splitting in Trilayer Graphene

Zhehao Ge, Sergey Slizovskiy, Frédéric Joucken, Eberth A. Quezada, Takashi Taniguchi, Kenji Watanabe, Vladimir I. Fal’ko, and Jairo Velasco, Jr.
Phys. Rev. Lett. 127, 136402 – Published 23 September 2021
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Abstract

Bloch states of electrons in honeycomb two-dimensional crystals with multivalley band structure and broken inversion symmetry have orbital magnetic moments of a topological nature. In crystals with two degenerate valleys, a perpendicular magnetic field lifts the valley degeneracy via a Zeeman effect due to these magnetic moments, leading to magnetoelectric effects which can be leveraged for creating valleytronic devices. In this work, we demonstrate that trilayer graphene with Bernal stacking (ABA TLG), hosts topological magnetic moments with a large and widely tunable valley g factor (gν), reaching a value gν1050 at the extreme of the studied parametric range. The reported experiment consists in sublattice-resolved scanning tunneling spectroscopy under perpendicular electric and magnetic fields that control the TLG bands. The tunneling spectra agree very well with the results of theoretical modeling that includes the full details of the TLG tight-binding model and accounts for a quantum-dot-like potential profile formed electrostatically under the scanning tunneling microscope tip.

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  • Received 28 March 2021
  • Accepted 17 August 2021

DOI:https://doi.org/10.1103/PhysRevLett.127.136402

© 2021 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Zhehao Ge1,*, Sergey Slizovskiy2,3,*, Frédéric Joucken1, Eberth A. Quezada1, Takashi Taniguchi4, Kenji Watanabe5, Vladimir I. Fal’ko2,3,6,†, and Jairo Velasco, Jr.1,‡

  • 1Department of Physics, University of California, Santa Cruz, California 95064, USA
  • 2Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
  • 3National Graphene Institute, University of Manchester, Booth Street East, Manchester M13 9PL, United Kingdom
  • 4International Center for Materials Nanoarchitectronics National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
  • 5Research Center for Functional Materials National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
  • 6Henry Royce Institute for Advanced Materials, Manchester M13 9PL, United Kingdom

  • *These authors contributed equally to this work.
  • Vladimir.Falko@manchester.ac.uk
  • jvelasc5@ucsc.edu

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Issue

Vol. 127, Iss. 13 — 24 September 2021

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