Invited talk

Spin-valley lifetime in graphene quantum dots
Guido Burkard

University of Konstanz, Germany

Graphene with its low nuclear spin density and weak spin-orbit coupling allows for long electron spin relaxation and coherence times. The spin and valley degrees of freedom of localized electrons can therefore be seen as potential embodiments of classical or quantum bits for computation. However, the formation of localized states in quantum dots requires some form of badgap engineering, and the mechanisms for spin and valley relaxation have not been completely understood so far. Bilayer graphene has an electrically controllable bandgap that allows for the formation of quantum dots. We present general theoretical considerations regarding the formation of quantum dots in graphene and report on recent progress in understanding the relevant physical mechanisms of spin and valley relaxation in electrostatically gated bilayer graphene quantum dots.

Figure 1: Log-log plot of the valley relaxation time T₁ as a function of perpendicular magnetic field B_⊥. The olive dots stand for the experimental data by Banszerus et al.