We present two newly designed 2D thermoelectric materials ScP and ScAs, which are stretchable up to 14%, stable up to 700 K, and can have lattice thermal conductivity as low as 0.45 W m−1 K−1.

We explore the structural, electronic, mechanical and thermoelectric properties of a new half Heusler compound, HfPtPb which is all metallic heavy element and has been recently been proposed to be stable [Nature Chem 7 (2015) 308]. In the present work, we employ density functional theory and semi-classical Boltzmann transport equations with constant relaxation time approximation. The mechanical properties such as Shear modulus, Young's modulus, elastic constants, Poisson's ratio, and shear anisotropy factor are investigated. The elastic and phonon properties reveal that this compound is mechanically and dynamically stable. Pugh's and Frantsevich's ratio demonstrates the ductile behavior andShear anisotropic factor reflects the anisotropic nature ofHfPtPb. The calculation of band structure predicts that this compound is semiconductor in nature with band gap 0.86 eV. The thermoelectric transport parameters such as Seebeck coefficient, electrical conductivity, and electronic thermal conductivity and lattice thermal conductivity have been calculated as a function of temperature. The highest value of Seebeck coefficient is obtained for n-type doping at optimal carrier concentration (10 20 e/cm 3 ).We predict the maximum value of figure of merit (0.25) at 1000 K. Our investigation suggests that this material is n-type semiconductor.

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Summary Stability and dynamics of structure, mechanical and thermoelectric properties of SiH monolayer have been reported in this work. After confirming the stability apprehensions, electronic structure calculations present the SiH as an indirect semiconducting monolayer with a bandgap of 2.19 eV. Calculations on elastic constant, deformation potential constant, effective mass, relaxation time, and mobility of charge carriers have been done to get the exact value of thermoelectric parameters. We analysed the variation of Seebeck coefficient, electrical conductivity and electronic thermal conductivity with respect to chemical potential at different temperatures and found that the high value of Seebeck coefficient and electrical conductivity along with low electronic thermal conductivity leads to a high value of ZeT ꞊ 2.185. SiH monolayer is being reported for the first time as a thermoelectric material and calculated thermoelectric properties show that SiH monolayer can be used efficiently in the field of thermoelectricity.

We study the effect of pressure on electronic and thermoelectric properties of Mg 2 Si using the density functional theory and Boltzmann transport equations. The variation of lattice constant, band gap, bulk modulus with pressure is also analyzed. Further, the thermoelectric properties (Seebeck coefficient, electrical conductivity, electronic thermal conductivity) have been studied as a function of temperature and pressure up to 1200 K. The results show that Mg 2 Si is an n-type semiconductor with a band gap of 0.21 eV. The negative value of the Seebeck coefficient at all pressures indicates that the conduction is due to electrons. With the increase in pressure, the Seebeck coefficient decreases and electrical conductivity increases. It is also seen that, there is practically no effect of pressure on the electronic contribution of thermal conductivity. The paper describes the calculation of the lattice thermal conductivity and figure of merit of Mg 2 Si at zero pressure. The maximum value of figure of merit is attained 1.83 × 10 −3 at 1000 K. The obtained results are in good agreement with the available experimental and theoretical results.