Doctor of Philosophy (Ph.D.)
In this dissertation, we study theoretically heterostructures based on Dirac mate- rials, i.e. materials, such as graphene in which the electrons behave as massless Dirac fermions at low energies. We first examine how the presence of long-range disorder affects the electronic ground state of a double layer graphene heterostruc- ture formed by two graphene layers separated by a thin dielectric film. We then identify the necessary conditions for the formation of an interlayer exciton conden- sate in such a system. We also comment on the effect of long-range disorder on the broken symmetry ground state induced by electron-electron interactions in bilayer graphene. Then, we study the transport properties of heterostructures obtained by stacking a graphene layer on the surface of a strong three-dimensional topological insulator (TI). In particular, we determine the non-equilibrium current-induced spin density accumulation for these systems using linear response theory and taking into account the effects of long- and short-range disorder both in the limit of strong and weak tunneling between the graphene layer and the TI. Finally, using some of the theoretical approaches developed to characterize the effect of long-range disorder in Dirac materials, we study the effect of long-range inhomogeneities in first-order phase transitions. In particular, we present a theoretical model to describe the ef- fect of inhomogeneities on the relaxation dynamics of vanadium dioxide films after a photo-induced metal-insulator transition.
© The Author
Rodriguez-Vega, Martin Alexander, "Disorder Effects in Dirac Heterostructures" (2016). Dissertations, Theses, and Masters Projects. William & Mary. Paper 1477068246.