A Dirac-Fermi liquid (DFL)--a doped system with Dirac spectrum--is an important example of a non-Galilean-invariant Fermi (FL). Real-life realizations DFL include, e.g., graphene, surface states three-dimensional (3D) topological insulators, and 3D Dirac/Weyl metals. We study the optical conductivity arising from intraband electron-electron scattering. It is shown that effective current relaxat...

Thermo-optical switches are of particular significance in communications networks where increasingly high switching speeds are required. Phase change materials (PCMs), in particular those based on paraffin wax, provide wealth of exciting applications with unusual thermally-induced switching properties, only limited by paraffin's rather low thermal conductivity. In this paper, the use of differe...