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 6 orbital symmetric and 10 orbital anti-symmetric states. We find that orbital symmetric states are lower in energy and separated by ≈0.4−0.8 meV from orbital anti-symmetric states. The symmetric multiplet exhibits an additional energy splitting of its 6 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 inter-valley scattering and 'current-current' interaction constants are of the same magnitude in BLG.
Cite
@article{arxiv.2106.08405,
title = {Probing two-electron multiplets in bilayer graphene quantum dots},
author = {Samuel Möller and Luca Banszerus and Angelika Knothe and Corinne Steiner and Eike Icking and Stefan Trellenkamp and Florian Lentz and Kenji Watanabe and Takashi Taniguchi and Leonid Glazman and Vladimir Fal'ko and Christian Volk and Christoph Stampfer},
journal= {arXiv preprint arXiv:2106.08405},
year = {2022}
}