Enhanced Lattice Symmetry via Mn Doping Boosts Electrical Transport Performance in Rhombohedral GeSe Thermoelectric Materials.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41285796.
- Also identified by DOI 10.1038/s41467-025-65364-0 and PMC identifier 12645029.
- Licence recorded as CC BY-NC-ND.
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Abstract
Low-symmetry thermoelectric material GeSe exhibits inherently low thermal conductivity but suppressed electrical transport properties. Here, we demonstrate that Mn doping in AgBiTe<sub>2</sub>-alloyed rhombohedral GeSe introduces band engineering and further significantly enhances lattice symmetry. Mn-induced resonant energy levels enhance the density of states effective mass and significantly optimize the Seebeck coefficient. Crucially, elevated lattice symmetry reduces deformation potential and weakens phonon-electron coupling, triggering a 185% surge in carrier mobility despite a ~1.2-fold increase in the effective mass. The synergistically optimized Seebeck coefficient and electrical conductivity enable the high-symmetry (GeMn<sub>0.005</sub>Se)<sub>0.9</sub>(AgBiTe<sub>2</sub>)<sub>0.1</sub> sample to achieve a record average power factor of ~17 μW cm<sup>-1</sup> K<sup>-2</sup> over 300-673 K while retaining low lattice thermal conductivity. Consequently, a maximum ZT of ~1.50 at 673 K and an average ZT of ~0.94 (300-673 K) are achieved, yielding a single-leg thermoelectric conversion efficiency of ~6.1% under a temperature difference of 325 K. This lattice symmetry manipulation through rational doping provides a universal pathway to promote phonon-electron decoupling and enhances thermoelectric performance in low-symmetry thermoelectric materials.