First-principles calculations to investigate optical and electrical properties of the half-Heusler materials TiXSn (X = Ni, Pt)

ABSTRACT

Thermoelectric compounds have the potential to produce electricity from waste heat, these materials are environmentally-friendly, which can play a key role on sustainable energy solution. This paper reports an investigation of electronic, optical and thermoelectric properties of two Half Heusler compounds TiNiSn and TiPtSn by employing density functional theory (DFT). Both compounds i.e. TiNiSn and TiPtSn exhibit an overestimated band gap with respective values 0.40 and 0.95 eV obtained by Tran Blaha modified Becke–Johnson functional (TB-mBJ) approximation, while, we found 0.113 and 0.84 eV within GGA + U (U = 6.13 eV) approximation, which are around other theoretical and experimental results. A detailed investigation of the obtained optical properties particularly, dielectric function, absorption, refractive index, and reflectivity of these compounds are given and discussed. Additionally, the transport properties of these compounds have been examined within Boltzmann statistics through BoltzTrap code, as well as certain thermoelectric parameters such as electrical conductivity, Seebeck coefficient and figure of merits are also determined. The obtained results reveal that the studied compounds are quite promising materials for thermoelectric applications.

KEYWORDS:

• Half Heusler alloys
• thermo-electric properties
• conductivity
• figure of merit
• optical properties

Disclosure statement

No potential conflict of interest was reported by the author(s).