TY  - JOUR
AU  - Bhui, Animesh
AU  - Biswas, Shuva
AU  - Paul, Sayan
AU  - Das, Subarna
AU  - Ghosh, Adrija
AU  - Swain, Diptikanta
AU  - Maji, Tapas Kumar
AU  - Pati, Swapan Kumar
AU  - Biswas, Kanishka
TI  - Atomic Off-Centering Driven Phonon-Glass Electron-Crystal-like Thermoelectric Transport in Entropy-Stabilized Quinary Telluride
JO  - Journal of the American Chemical Society
VL  - 147
IS  - 32
SN  - 0002-7863
CY  - Washington, DC
PB  - ACS Publications
M1  - PUBDB-2025-04421
SP  - 29542 - 29553
PY  - 2025
AB  - Entropy engineering offers innovative design opportunities for synthesizing new thermoelectric materials by integrating conflicting physical parameters. Optimization of configurational entropy holds the potential to simultaneously reduce the thermal conductivity through inherent disorder and enhance the Seebeck coefficient by symmetrizing the crystal lattice, both of which are crucial to augmenting the thermoelectric performance of a crystalline solid. Here, we synthesized an entropy-stabilized quinary metal telluride single crystal, AgGeSnSbTe4, exhibiting an intriguing phonon-glass electron-crystal (PGEC)-like thermoelectric transport. Synchrotron X-ray pair distribution function (X-PDF) analysis infers that entropy-driven stabilization generates a highly symmetric rock-salt average structure but is accompanied by cation distortion in the local structure, which further enhances with temperature, reminiscent of emphanisis. Local lattice distortion-induced anharmonicity with considerable atomic disorder leads to glass-like lattice thermal conductivity, where the phonon mean free path approaches the interatomic distance. Phonon dispersion analysis corroborates the presence of local symmetry breaking, primarily driven by the off-centering displacement of Ge atoms due to the stereochemical expression of the 4s2 lone pair, which results in local ferroelectric lattice instability. Notably, the glassy thermal conductivity is complemented by good electrical conductivity and a high Seebeck coefficient, enabled through long-range atomic order within the average cubic framework. The realization of the PGEC paradigm results in a promising thermoelectric figure-of-merit (zT) of ∼1.2 at 670 K in the Bridgman-grown AgGeSnSbTe4 crystal. 
LB  - PUB:(DE-HGF)16
C6  - pmid:40729560
DO  - DOI:10.1021/jacs.5c10635
UR  - https://bib-pubdb1.desy.de/record/639320
ER  -