  Transition metal dichalcogenides (TMDCs) belong to technologically important
compounds. We have explored the structural, elastic, bonding, optoelectronic
and some thermo-physical properties of ZrX2 (X = S, Se, Te) TMDCs in details
via ab-initio technique in this study. Elastic anisotropy indices, atomic
bonding character, optoelectronic properties and thermo-physical parameters
including melting temperature and minimum phonon thermal conductivity are
investigated for the first time. All the TMDCs under investigation possess
significant elastic anisotropy and layered structural features. ZrX2 (X = S,
Se, Te) compounds are fairly machinable, and ZrS2 and ZrSe2 are moderately
hard. ZrTe2, on the other hand, is significantly softer. Both covalent and
ionic bondings contribute in the crystals. Electronic band structure
calculations display semiconducting behavior for ZrS2 and ZrSe2 and metallic
behavior for ZrTe2. Energy dependent optoelectronic parameters exhibit good
correspondence with the underlying electronic energy density of states
features. ZrX2 (X = S, Se, Te) compounds absorb ultraviolet radiation
effectively. The reflectivity spectrum, R(w), remains over 50% in the energy
range from 0 eV to 20 eV for ZrTe2. Therefore, this TMDC has wide band and
nonselective high reflectivity and can be used as an efficient reflector to
reduce solar heating. Debye temperature, melting point and minimum phonon
thermal conductivity of the compounds under study are low and show excellent
correspondence with each other and also with the elastic and bonding
characteristics.
