Abstract

Quantum nanostructures, e.g., quantum wires and quantum dots, are needed for applications in quantum information processing devices, such as transistors or qubits. In gapped bilayer graphene (BLG), one can confine charge carriers purely electrostatically, inducing smooth confinement potentials and limiting edge-induced perturbances while allowing gate-defined control of the confined structure. I will discuss charge transport in BLG nanostructures with electrostatically confined quantum dots. We investigated both theoretically and in collaboration with experiments how the BLG dots’ highly degenerate single- and two-electron spin and valley multiplets, which depend on, e.g., the displacement field and the electron-electron interactions, manifest in tunnelling transport. This way, we shed light on microscopic material parameters of BLG while opening the field for using the dots’ rich spin and valley multiplets for quantum information storage and processing.


1) Theory of tunneling spectra for a few-electron bilayer graphene quantum dot

A. Knothe, L. I. Glazman, V. I. Fal’ko, arXiv:2104.03399


2) Probing two-electron multiplets in bilayer graphene quantum dots

S. Möller, L. Banszerus, A. Knothe, C. Steiner, E. Icking, S. Trellenkamp, F. Lentz, K. Watanabe, T. Taniguchi, L. Glazman, V. Fal’ko, C. Volk, C. Stampfer, arXiv:2106.08405


3) Quartet states in two-electron quantum dots in bilayer graphene

A. Knothe, V. Fal’ko, Phys. Rev. B 101, 235423 (2020),


4) Shell Filling and Trigonal Warping in Graphene Quantum Dots

R. Garreis, A. Knothe, C. Tong, M. Eich, C. Gold, K. Watanabe, T. Taniguchi, V. Fal’ko, T. Ihn, K. Ensslin, A. Kurzmann, Phys. Rev. Lett. 126, 147703 (2021)


5) Tunable valley splitting and bipolar operation in graphene quantum dots

C. Tong, R. Garreis, A. Knothe, M. Eich, A. Sacchi, K. Watanabe, T. Taniguchi, V. Fal’ko, T. Ihn, K. Ensslin, A. Kurzmann, Nano Lett. 2021, 21, 2, 1068–1073 (2021)