Entropy engineering of SnTe towards high-entropy thermoelectrics
Jian
He
Department
of
Physics
and
Astronomy
Clemson
University
Monday,
January
13,
2019
10:00
a.m.
C2-361
(Reading
Room)
Abstract:
High entropy thermoelectrics is a synergy of thermoelectric materials research and high entropy alloys. In this talk, I briefly review the role of entropy in thermoelectrics, the four core effects of high entropy alloys, and present a case study in SnTe. Upon entropy engineering, the solubility of Mn is extended in favor of carrier concentration, band gap, and band convergence, which compensate for the degraded carrier mobility; the carrier scattering mechanism crossovers from electron-phonon scattering to alloying scattering; despite a simple fcc structure, the lattice thermal conductivity is suppressed by multi-scale hierarchical microstructures and severe lattice distortion. As a result, a promising figure of merit ~1.42 is attained in (Sn0.74Ge0.2Pb0.1)0.75Mn0.275Te at 900 K. These results attest to the efficacy of entropy engineering towards high-entropy thermoelectrics.
