Charge and current responses of spin-orbit coupled two-dimensional materials

In the present thesis the single- and many-particle properties of three different two-dimensional materials, graphene, a monolayer of molybdenum disulfide, and p-doped III-V semiconductor quantum wells, are investigated. In contrast to earlier works we explicitly take into account the effect of the various types of spin-orbit interactions and their influence on the dielectric properties. We show how spin-orbit coupling in two-dimensional systems might be used to change the plasmon energy and lifetime, which in turn might be interesting in view of the promising new research field known as plasmonics. In the first part of the work we present closed analytical expressions for the dielectric function and the current-current correlation function of graphene and study in great detail the effect of spin-orbit coupling on the plasmon spectrum and the screening behavior of charged impurities. In the second part numerical results for the dielectric functions of monolayer molybdenum disulfide, GaAs, and InAs, are discussed and possible applications such as plasmon transistors and filters are described. The influence of a strong time-dependent electromagnetic field on the single-particle properties of graphene is investigated in the final part. Here we describe a way to open and close the band gap in the energy spectrum of graphene by changing the magnitude of the electric field