Electronic Structure-, Phonon Spectrum-, and Effective Mass- Related Thermoelectric Properties of PdXSn (X = Zr, Hf) Half Heuslers

Abstract

We hereby discuss the thermoelectric properties of PdXSn(X = Zr, Hf) half Heuslers in relation to lattice thermal conductivity probed under effective mass (hole/electrons) calculations and deformation potential theory. In addition, we report the structural, electronic, mechanical, and lattice dynamics of these materials as well. Both alloys are indirect band gap semiconductors with a gap of 0.91 eV and 0.82 eV for PdZrSn and PdHfSn, respectively. Both half Heusler materials are mechanically and dynamically stable. The effective mass of electrons/holes is (0.13/1.23) for Zr-type and (0.12/1.12) for Hf-kind alloys, which is inversely proportional to the relaxation time and directly decides the electrical/thermal conductivity of these materials. At 300K, the magnitude of lattice thermal conductivity observed for PdZrSn is 15.16 W/mK and 9.53 W/mK for PdHfSn. The highest observed ZT value for PdZrSn and PdHfSn is 0.32 and 0.4, respectively.

Electronic, Elastic, and Thermoelectric Properties of Half-Heusler Topological Semi-Metal HfIrAs from First-Principles Calculations

“…The dimensionless figure of merit (ZT) of HfIrAs at 300 K, 600 K, and 800 K is 0.23, 0.5, and 0.57, respectively (see Figure 4d). The ZTs obtained in this work are comparable to that of a good thermoelectric candidate from previous similar work [78]. The ZT of HfIrAs increases with an increase in temperature, and the ZT of 0.57 shows that HfIrAs is a good thermoelectric material.…”

A first-principles assessment of the thermoelectric properties in half-heusler compound NbIrSn

“…At a temperature of 400 K, the NbIrSn compound exhibits maximum Seebeck coefficient values of approximately ∼920 μV/K for p-type and ∼755 μV/K for n-type regions within the range of examined chemical potentials. The values mentioned are comparable to those observed in PdXSn (X = Zr, Hf) [73] but lower than those in PtXSn (X = Zr, Hf) [74]. With increasing temperature, the maximum values of the Seebeck coefficient decrease.…”

Thermoelectric Properties of 2D Sn2SSe$Sn_{2}SSe$ Monolayer

“…The chemical stability is determined by formation energy that is specified as the difference between the energy of the compound and the sum of energies of the elemental constituents. [37][38][39] ΔE f = [E(Sn 2 SSe) − nE(Sn 2 ) − nE(S) − nE(Se)]∕n (7) where E(Sn 2 SSe), E(Sn 2 ), E(S), and E(Se) are total energy of Sn 2 SSe, Sn 2 , S, and Se, respectively. The computed value of formation energy is −1.684.…”

“…The chemical stability is determined by formation energy that is specified as the difference between the energy of the compound and the sum of energies of the elemental constituents. [ 37–39 ] $$$$\begin{equation} \Delta E_f =[E(Sn_{2}SSe)-nE(Sn_{2})-nE(S)-nE(Se)]/n \end{equation}$$$$where E($$Sn_{2}SSe$$), E($$Sn_{2}$$), E(S), and E(Se) are total energy of $$Sn_{2}SSe$$, $$Sn_{2}$$, S, and Se, respectively. The computed value of formation energy is −1.684.…”