Title: Optical signature of Weyl electronic structures in tantalum pnictides Ta$Pn$ ($Pn=$ P, As),
Abstract: To investigate the electronic structure of Weyl semimetals Ta$Pn$ ($Pn=$P,
As), optical conductivity [$\sigma(\omega)$] spectra are measured over a wide
range of photon energies and temperatures, and these measured values are
compared with band calculations. Two significant structures can be observed: a
bending structure at $\hbar\omega\sim$85 meV in TaAs, and peaks at
$\hbar\omega\sim$ 50 meV (TaP) and $\sim$30 meV (TaAs). The bending structure
can be explained by the interband transition between saddle points connecting a
set of $W_2$ Weyl points. The temperature dependence of the peak intensity can
be fitted by assuming the interband transition between saddle points connecting
a set of $W_1$ Weyl points. Owing to the different temperature dependence of
the Drude weight in both materials, it is found that the Weyl points of TaAs
are located near the Fermi level, whereas those of TaP are further away.