In this work we calculate the thermoelectric figure of merit of XHfPb (X= Ni, Pd, and Pt) by computing the both the power factor and the lattice thermal conductivity by first principles. We make reasonable approximations: we use the Constant Relaxation Time Approximation (CRTA) to compute the electron transport contribution and the modified Debye-Callaway model to calculate the thermal lattice conductivity. We also report the dielectric properties of these semiconductors and the mode Gruneisen parameters. Not surprisingly we find that the average Gruneisen coefficient correlates with the thermal conductivity. Next, we consider a realistic relaxation timer-and carrier concentration n from experimental data on ZrHfPb and obtain the figure of merit ZT as a function of temperature. Our main finding is that despite the Pt is isoelectronic with Ni and Pd, the ZT of PtHfPb is larger and behaves differently from the other two materials, suggesting that PtHfPb is better suited for high temperature thermoelectric generators.

Electronic and phonon contributions to the Thermoelectric properties of newly discovered half-Heusler alloys XHfPb (X= Ni, Pd, and Pt) / P.O. Adebambo, G.A. Adebayo, R. Guerra, D. Ceresoli. - In: JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS. - ISSN 0022-3697. - 174:(2023 Mar), pp. 111196.1-111196.9. [10.1016/j.jpcs.2022.111196]

Electronic and phonon contributions to the Thermoelectric properties of newly discovered half-Heusler alloys XHfPb (X= Ni, Pd, and Pt)

R. Guerra
Penultimo
;
2023

Abstract

In this work we calculate the thermoelectric figure of merit of XHfPb (X= Ni, Pd, and Pt) by computing the both the power factor and the lattice thermal conductivity by first principles. We make reasonable approximations: we use the Constant Relaxation Time Approximation (CRTA) to compute the electron transport contribution and the modified Debye-Callaway model to calculate the thermal lattice conductivity. We also report the dielectric properties of these semiconductors and the mode Gruneisen parameters. Not surprisingly we find that the average Gruneisen coefficient correlates with the thermal conductivity. Next, we consider a realistic relaxation timer-and carrier concentration n from experimental data on ZrHfPb and obtain the figure of merit ZT as a function of temperature. Our main finding is that despite the Pt is isoelectronic with Ni and Pd, the ZT of PtHfPb is larger and behaves differently from the other two materials, suggesting that PtHfPb is better suited for high temperature thermoelectric generators.
Density functional theory; Thermoelectrics; Phonons; Thermal conductivity; Heusler alloys;
Settore FIS/03 - Fisica della Materia
   Transnational Access Programme for a Pan-European Network of HPC Research Infrastructures and Laboratories for scientific computing
   HPC-EUROPA3
   European Commission
   Horizon 2020 Framework Programme
   730897
mar-2023
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/970657
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