Assessing the thermoelectric properties of ScRhTe half-heusler compound

Abstract

We investigate structural, elastic, electronic and thermoelectric properties of ScRhTe with frame work of density functional theory and Boltzmann equations. The physical properties such as elastic constants, bulk modulus, shear modulus, Young's modulus and Poisson's ratio of ScRhTe compound are calculated. The elastic properties of ScRhTe reveal that this compound is mechanically stable. Further, the phonon calculation of ScRhTe indicates that it also dynamically stable. The band structure as well as DOS spectra indicates that ScRhTe compound has a semiconductor nature. The calculated energy band gap of ScRhTe compound is 0.8eV.The thermoelectric properties such as Seebeck coefficient, electrical conductivity scaled by relaxation time, power factor scaled by relaxation time and electronic thermal conductivity has been investigated with variation of carrier concentration and temperature. The highest power factor obtained at 1200 K is 11.9 × 1011V2SK−2ms−1 at optimum carrier concentration n∼1.3 × 1021cm−3 for n-type ScRhTe. The maximum dimensionless figure of merit for n-type ScRhTe is 0.63. Using the slack equation, the lattice thermal conductivity of ScRhTe is also estimated. At room temperature, ScRhTe attains low thermal conductivity as compared to well know ZrNiPb half heusler compound. The lower lattice thermal conductivity of ScRhTe suggest that this compound may be act as good thermoelectric material. Our results suggested that power factor can't improve further when electron carrier concentration reaches to n∼1.3 × 1021cm−3 and hole carrier concentration reaches to n∼7.5 × 1020cm−3. This is the first quantitative theoretical estimation of these properties.