Free-carrier dynamics in Au${}_2$Pb probed by optical conductivity measurements

Abstract

We measured the optical reflectivity of the Dirac material Au${}_2$Pb in a broad frequency range (30 - 48 000 cm${}^{-1}$) for temperatures between 9 and 300 K. The optical conductivity, computed from the reflectivity, is dominated by free-carrier contributions from topologically trivial bulk bands at all temperatures. The temperature-independent total plasma frequency of these carriers is 3.9 $\pm$ 0.2 eV. Overall, optical response of Au${}_2$Pb is typically metallic with no signs of localization and bad-metal behavior.

10 pages, IOP style