Breaking New Ground in Bulk Properties of TaAs.

Weyl semimetals are materials in which electrons exhibit the physics of Weyl fermions, results in novel and promising physical effects like the chiral magnetic effect and Fermi arc surface states. TaAs has received particular attention as the first Weyl semimetal to be grown and the first to display chiral magnetic effect. The availability of mm-scale TaAs crystals has resulted in extensive charadterization of the bulk physics using far- and mid-IR spectroscopy. Consequently, one would naively expect there to be little characterization of interest left for the bulk of TaAs.

Recently, growers at the National Renewabl Energy Laboratory were able to grow large-area films of TaAs. These samples not only present an opportunity to study the novel surface states of TaAs but, due to the large doping of the samples, allow us to explore an entirely new range of these materials band structure.

In this work, I present my group's initial optical characterization of thin films of TaAs.