  BaAgAs is a ternary Dirac semimetal which can be tuned across a number of
topological orders. In this study we have investigated the bulk physical
properties of BaAgAs using density functional theory based computations. Most
of the results presented in this work are novel. The optimized structural
parameters are in good agreement with previous results. The elastic constants
indicate that BaAgAs is mechanically stable and brittle in nature. The compound
is moderately hard and possesses fair degree of machinability. There is
significant mechanical/elastic anisotropy in BaAgAs. The Debye temperature of
the compound is medium and the phonon thermal conductivity and melting
temperature are moderate as well. The bonding character is mixed with notable
covalent contribution. The electronic band structure calculations reveal clear
semimetallic behavior with a Dirac node at the Fermi level. BaAgAs has a small
ellipsoidal Fermi surface centered at the G-point of the Brillouin zone. The
phonon dispersion curves show dynamical stability. There is a clear phonon band
gap between the acoustic and the optical branches. The energy dependent optical
constants conform to the band structure calculations. The compound is an
efficient absorber of the ultraviolet light and has potential to be used as an
anti-reflection coating. Optical anisotropy of BaAgAs is moderate. The computed
repulsive Coulomb pseudopotential is low indicating that the electronic
correlations in this compound are not strong.
