Dresden 2017 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 26: Two-Dimensional Materials III (joint session DS, HL, TT, organized by HL)

TT 26.5: Talk

Tuesday, March 21, 2017, 10:30–10:45, POT 51

Spin Degenerate Regimes for Single Two-Dimensional Quantum Dots on Transition Metal Dichalcogenide Monolayers — •Matthew Brooks and Guido Burkard — Department of Physics, University of Konstanz, D-78464, Germany

Strong spin orbit coupling in transition metal dichalcogenides (TMDCs) monolayers results in spin resolvable band structures about the K (K′) valleys such that the eigenbasis of a 2D quantum dot (QD) on a TMDC monolayer in zero field is described by the Kramers pairs |+⟩=|K′↑⟩,|K↓⟩ and |−⟩=|K↑⟩,|K′↓⟩ . This coupling limits the usefulness of single TMDC QDs as qubits due to the inherent difficulty of generating superposition states of the valley degree of freedom. Possible regimes of spin degenerate states overcoming the spin orbit coupling in monolayer TMDC QDs are investigated in both zero field, where the spin and valley degrees of freedom become fourfold degenerate, and in some magnetic field, localised to the K′ valley. Such regimes are shown to be achieved in MoS₂, where the spin orbit coupling is sufficiently low that the spin resolved conduction bands intersect at points about the K (K′) valleys and as such may be exploited by selecting suitable critical dot radii.