Dresden 2017 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 34: Two-dimensional materials III (joined session with TT)

HL 34.12: Talk

Tuesday, March 21, 2017, 13:00–13:15, POT 51

Exchange Interaction for Quantum Dots in TMDCs — •Alessandro David, Andor Kormanyos, and Guido Burkard — Department of Physics, University of Konstanz, D-78457 Konstanz, Germany

We study the properties of double quantum dots in Transition Metal Dichalcogenides (TMDCs) where trapped electrons comprise not only the usual spin and valley degrees of freedom, but also a spin-orbit splitting in the spectrum. The spin-orbit coupling splits the four-fold spin and valley degeneracy into two Kramers pairs with correlated spin and valley states. We consider two different situations where the spin-orbit splitting is either much larger or comparable to the tunneling. Our aim is to use such systems filled with only two electrons for quantum information processing. In the case of large spin-orbit splitting, it turns out that there is a fourfold degenerate ground state (well separated from higher states) where, with a simple redefinition of Pauli matrices, we can obtain a CNOT gate in the same way it was obtained in the quantum computer proposed by Loss and DiVincenzo. In the case of small spin-orbit splitting, we have to consider a 16 dimensional subspace, but it is still possible to obtain a unitary evolution operator, that also depends on the value of spin-orbit splitting.