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HL: Fachverband Halbleiterphysik

HL 70: Spin phenomena in semiconductors

HL 70.7: Vortrag

Donnerstag, 19. März 2020, 16:30–16:45, POT 251

Spin relaxation induced by valley-orbit coupling in a single Si quantum dot — •Amin Hosseinkhani and Guido Burkard — Department of Physics, University of Konstanz, Germany

The spin of isolated electrons in Silicon quantum dot heterostructures is a promising candidate for quantum information processing. While silicon offers weak spin-orbit coupling and nuclear-spin free isotopes, the valley degree of freedom in silicon couples to spin and can degrade the qubit performance by opening a relaxation channel. We build on the effective mass theory and find exact solutions for the envelope function of a single quantum dot along the applied electric field. We take into account a few miscuts at the Si/barrier interface and study how the wavefunction evolves in the magnetic field. We then obtain the valley phase and splitting for a single quantum dot spin qubit as a function of the applied magnetic and electric field. These enable us to develop the theory of spin-relaxation induced by valley-orbit coupling. We show that it is important to consider all four physical spin-valley states into the qubit logical states in order to describe the qubit relaxation.