NBIA CMT Seminar: David Abergel (Nordita) – University of Copenhagen

NBIA CMT Seminar: David Abergel (Nordita)

Excitonic condensation in double layer graphene: the role of disorder

The existence of an excitonic condensate at zero magnetic field in double layer graphene has been predicted theoretically, but has not been observed in experiment. We discuss, from a theoretical point of view, the conditions under which this condensate has a critical temperature high enough to allow detection. Crucially, disorder arising from charged impurities and corrugation in the lattice structure affects the formation of the condensate via the induced charge inhomogeneity. We employ mean-field BCS theory to describe the condensate formation, and a numerical Thomas-Fermi-Dirac theory to describe the disorder. Combining these calculations gives realistic estimates of the likelihood of observing the condensate in different experimental situations.
If time permits, we shall also describe a different theme: The role of the spin-orbit interaction in Jackiw-Rebbi modes in two dimensional materials.