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

Research output: Contribution to journalArticlepeer-review

  • External authors:
  • Zhehao Ge
  • Fredric Joucken
  • Eberth A. Quezada
  • Takashi Taniguchi
  • Kenji Watanabe
  • Jairo Velasco Jr

Abstract

Bloch states of electrons in honeycomb two-dimensional crystals with multi-valley 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, reaching a value ~1050 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 modelling 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.

Bibliographical metadata

Original languageEnglish
JournalPhysical Review Letters
DOIs
Publication statusPublished - 23 Sep 2021