Effect of electron-phonon scattering, pressure and alloying on the thermoelectric performance of TmCu${}_3$Ch${}_4$ (Tm=V, Nb, Ta; Ch=S, Se, Te)

Abstract

The demand for green energy increases day by day due to environmental concern and thermoelectric (TE) materials are one of the eco-friendly energy resources. Few authors reported high TE performance in TmCu${}_3$Ch${}_4$, reaching the figure of merit (ZT) above 2 at 1000K, from first-principles calculations neglecting electron-phonon scattering, spin-orbit coupling effect (SOC), and energy-dependent carrier lifetime. Here, thermoelectric transport properties of TmCu${}_3$Ch${}_4$ are reinvestigated through considering these parameters, and significant discrepancies are found. The ZT of p-type TaCu${}_3$Te${}_4$ can reach ~3 at 1000K among these compounds due to its low lattice thermal conductivity (${\kappa }_l$) (0.38 W m-1 K-1). Interestingly, the value of ${\kappa }_l$ is reduced to 0.17 W m-1 K-1 through 1 GPa pressure while the power factor is slightly improved due to bandgap reduction, leading to an extraordinary ZT~5.5 at 1000K. Although the substitution of Se causes a slight reduction of ${\kappa }_l$ to ~0.3 W m-1 K-1, the power factor is reduced significantly due to the dramatic reduction of DOS near Fermi level, which leads to lower the Seebeck coefficient largely and increase electrical conductivity slightly.

References in corpus (4)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• BoltzTraP. A code for calculating band-structure dependent quantities
• Necessary and Sufficient Elastic Stability Conditions in Various Crystal Systems
• Distribution of phonon lifetime in Brillouin zone

Cited by in corpus (3)

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• Newly synthesized 3D boron-rich chalcogenides B12X (X = S, Se): Theoretical characterization of physical properties for optoelectronic and mechanical applications