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HL: Fachverband Halbleiterphysik

HL 65: 2D Materials and their Heterostructures III (joint session DS/HL)

HL 65.6: Vortrag

Donnerstag, 19. März 2020, 12:15–12:30, CHE 89

Interacting two-electron states in electrostatically confined bilayer graphene quantum dots — •Angelika Knothe and Vladimir Fal'ko — National Graphene Institute, University of Manchester, Manchester M13 9PL, United Kingdom

Successfully utilizing the properties of two-dimensional materials in quantum nanostructure devices could lead to unprecedented electronics applications. We study the possible states of two interacting electrons in a quantum dot electrostatically confined in gapped bilayer graphene. The properties of the material's electronic structure, such as the three minivalleys around each valley, and the corresponding orbital magnetic moment, translate into the features of the dot states. In the weakly gapped case, the single-particle level scheme is that of an almost quadratic band, featuring a singly-degenerate ground state and angular momentum duplet degeneracies. For a sufficiently strong gap, threefold degenerate "minivalley triplets" emerge. For two electrons in the dot, the long-range part of the screened Coulomb interaction defines the orbital configuration of the interacting two-particle state. Short-range contributions breaking the symmetries on the lattice scale determine the ordering in spin and valley space. We identify the set of orbital, spin, and valley levels of the interacting two-particle states.