Insight to structural, electronic, optical and thermoelectric properties of NaCaSb and KCaSb half Heusler compounds: a DFT approach
D. Behera, S. K. Mukherjee1)
Department of Physics, Birla Institute of Technology, 835215 Mesra, Ranchi, India
Abstract
Full-potential, linearized augmented plane wave approach (FP LAPW), as employed in Wien2K
code was utilized to analyze structural, elastic, optoelectronic, and transport features of NaCaSb
and KCaSb half-Heusler (HH) compounds. Generalized gradient approximation (GGA) was considered
for structural optimization. The predicted lattice constants are in line with the prior
theoretical and experimental findings. The examined NaCaSb and KCaSb compounds are
inherently ductile and mechanically stable. The investigated HHs are semiconductors with a band
gap 1.27 and 1.23 eV for NaCaSb and KCaSb respectively, within the modified Becke?Johnson (mBJ) approximation.
Calculated optical characteristics of NaCaSb and KCaSb point to their potential applicability in
optoelectronic devices. Thermoelectric features were analyzed employing the Boltzmann transport
provided in the BoltzTraP software. At room temperature, the significant figure of merit (ZT)
values indicates that the investigated NaCaSb and KCaSb can be used for fabricating
thermoelectric devices with the highest possible efficiency.