High entropy alloys (HEA) have recently attracted much attention in the fields of materials science and engineering [1-6]. A bibliographic search from the Chemical abstract Service database indicates that more than 11000 papers have been published on HEA since 2002. Most of these references deals with materials containing mainly transition metal elements (Ti, Cr, Fe, Cu, Mo, Co, Ni, Nb, Ta, Pt, …), occasionally combined with metals or non-metals of the principal elements ((Al, Si, P, …).
Because of the lattice distortion effects, which reduce phonon velocity and enhance the scattering of phonons, high-entropy alloys generally have low lattice thermal conductivity [7-9]. As high-entropy sulfides, Cu5Sn1.2MgGeZnS9 has been reported with a ZT value of 0.58 at 773 K [10]. The high-entropy metal chalcogenide (Ag,Pb,Bi)(S,Se,Te) alloy has been investigated and it was found that it is a n-type semiconductor with low κL and good power factor resulting in a figure of merit of 0.54 at 723 K [11]. Recently, a n-type PbSe-based high-entropy material formed by entropy-driven structural stabilization has been studied for its thermoelectric properties. The ZT value was found to reach 1.8 at 900 K [12].
Modelling HEAs transport properties constitutes a challenge due to the large cell size that must be simulated. Nonetheless, we have recently undertaken the investigation of PbSnTeSe as a HEA (Figure 1) by combining first-principles calculations and on-the-fly machine learning technique with the semiclassical Boltzmann transport theory and Green-Kubo theory. The thermoelectric transport properties of PbSnTeSe high entropy alloy have been thoroughly investigated. In this presentation will be presented the methodology employed and the electronic and thermal transport coefficients of PbSnTeSe high entropy alloy will be discussed in detail.
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