  Since the successful synthesis of the MoSSe monolayer, which violated the
out-of-plane mirror symmetry of TMDs monolayers, considerable and systematic
research has been conducted on Janus monolayer materials. By systematically
analyzing the LaBrI monolayer, we are able to learn more about the novel Janus
material by focusing on the halogen family next to group VIA (S, Se, Te). The
structural optimizations have been carried out using the FP-LAPW (Full
Potential Linear Augmented Plane Wave) basis, as implemented in the ELK using
tb-mBJ exchange correlation potential. Computed structural parameters are in
good comparison with literature reports. Further, optimized crystal structures
were used for computing effect of strain on electronic and thermoelectric
properties using pseudo potential based Quantum espresso code. Dynamical
stability predicts material can withstand strain upto 10% strain. Computed
electronic structure reveals material to be indirect wide bandgap ferromagnetic
material with magnetic moment 1{\mu}B. With increase in the biaxial tensile
strain the band gap increases. Furthermore, the computed magneto-thermoelectric
properties predicts high Seebeck coefficient of ~ 400 {\mu}V/K and low thermal
conductivity of ~ 1.13 X 1014 W/msK in LaBrI which results high ZT of ~ 1.92
with 8% strain at 800 K with p-type doping. Thus, present study supports the
fact that tensile strain on ferromagnetic LaBrI material can further enhance TE
properties and making it to be a promising material for TE applications at
higher temperature.
