title: Universality of Plasmon Excitations in Dirac Semimetals.
abstract: We investigate the properties of the collective plasmon excitations in Dirac semimetals by using the methods of relativistic field theory. We find a strong and narrow plasmon excitation whose frequency is in the terahertz (THz) range which may be important for practical applications. The properties of the plasmon appear universal for all Dirac semimetals, due to the large degeneracy of the quasiparticles and the small Fermi velocity, v_{F}≪c. This universality is closely analogous to the phenomenon of "dimensional transmutation" that is responsible for the emergence of dimensionful scales in relativistic field theories such as quantum chromodynamics.
authors.affiliation: Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800, USA.|Department of Physics, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Dmitri E
authors.initials: DE
authors.lastname: Kharzeev
authors.affiliation: Department of Physics, Brookhaven National Laboratory, Upton, New York 11973, USA.|RIKEN-BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Pisarski
authors.affiliation: RIKEN-BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.|Physics Department, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
authors.forename: Ho-Ung
authors.initials: HU
authors.lastname: Yee