  Various ternary chalcogenide systems and their properties are one of the hot
topics for researchers nowadays. In this article, one of the ternary
chalcogenide compounds, CdTl2Te4 is studied including its electronic structures
and optical properties via first principles calculations using SIESTA code. The
structure of the compound has a tetragonal crystal system and the unit cell is
periodic in all directions. The band structure showed it is a direct band gap
semiconductor which is explained by the density of states. The energy gap
obtained is seen to increase on employing external electric field perpendicular
to the xy plane, but does not increase on increasing the magnitude of field
strength. The optical properties which includes absorption coefficient,
reflectance, real & imaginary parts of dielectric function, refractive index
and extinction coefficient were calculated for polarized light both in plane
and out of the plane, but the interesting modulation in properties were seen
for the latter which can open up applications of the compound in UV absorbers,
making solar cells, etc. So, the compound being a narrow-gap semiconductor
along with its tunable electronic and optical properties can have potential
application in the fields such as optoelectronics.
