Impact of competing energy scales on the shell-filling sequence in elliptic bilayer graphene quantum dots

Abstract

We report on a detailed investigation of the shell-filling sequence in electrostatically defined elliptic bilayer graphene quantum dots (QDs) in the regime of low charge carrier occupation, $N\le 12$, by means of magnetotransport spectroscopy and numerical calculations. We show the necessity of including both short-range electron-electron interaction and wavefunction-dependent valley g-factors for understanding the overall fourfold shell-filling sequence. These factors lead to an additional energy splitting at half-filling of each orbital state and different energy shifts in out-of-plane magnetic fields. Analysis of 31 different BLG QDs reveals that both valley g-factor and electron-electron interaction induced energy splitting increase with decreasing QD size, validating theory. However, we find that the electrostatic charging energy of such gate-defined QDs does not correlate consistently with their size, indicating complex electrostatics. These findings offer significant insights for future BLG QD devices and circuit designs.

11 pages, 9 figures

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Cited by in corpus (7)

• Extended Hubbard model describing small multi-dot arrays in bilayer graphene
• Switching spin filling sequence in a bilayer graphene quantum dot through trigonal warping
• Phonon-limited valley life times in single-particle bilayer graphene quantum dots
• Tuning confined states and valley g-factors by quantum dot design in bilayer graphene
• Electric field tunable spin-orbit gap in a bilayer graphene/WSe${}_2$ quantum dot
• The role of antisymmetric orbitals and electron-electron interactions on the two-particle spin and valley blockade in graphene double quantum dots
• Gate-defined Kondo lattices with valley-helical quantum dot arrays