Probing Two-Electron Multiplets in Bilayer Graphene Quantum Dots

Physical Review Letters, vol. 127, pp. 256802

Abstract

We report on finite bias spectroscopy measurements of the two-electron spectrum in a gate defined bilayer graphene (BLG) quantum dot for varying magnetic fields. The spin and valley degree of freedom in BLG give rise to multiplets of six orbital symmetric and ten orbital antisymmetric states. We find that orbital symmetric states are lower in energy and separated by ≈ 0.4-0.8 meV from orbital antisymmetric states. The symmetric multiplet exhibits an additional energy splitting of its six states of ≈ 0.15-0.5 meV due to lattice scale interactions. The experimental observations are supported by theoretical calculations, which allow to determine that intervalley scattering and "current-current" interaction constants are of the same magnitude in BLG.

Authors 2

1. Angelika Knothe

   University of Manchester

   Affiliation as printed

   National Graphene Institute, University of Manchester, Manchester M13 9PL, United Kingdom

2. Vladimir I. Fal’ko

   University of Manchester · Henry Royce Institute

   Affiliation as printed

   Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom

   Henry Royce Institute for Advanced Materials, University of Manchester, Manchester M13 9PL, United Kingdom

   National Graphene Institute, University of Manchester, Manchester M13 9PL, United Kingdom