Study of Dirac Electrons in BiPd and Graphene using Angle-Resolved Photoemission Spectroscopy.

In this talk, I will describe our recent efforts to understand the properties of Dirac electrons in BiPd and Graphene using angle-resolved photoelectron spectroscopy (ARPES). Previous ARPES studies have already provided a lot of insight into these material systems. But at times conflicting results have been reported. In particular, the dimensional nature of Dirac state in BiPd has not unambiguously established. In the case of graphene, ARPES spectra of epitaxially grown samples deviate from the theoretically predicted conical structure. To explain this observation various ideas have been proposed (formation of plasmaron quasiparticles, substrate-induced bandgap opening, etc.). In this presentation, I will show that our recent studies can partly answer some of these questions.