2025/08/12 by Wu Xiong, Zhonghao Xia, Xiong, Wu +6
Engineering · Materials Science · Physics and Astronomy · #Advanced Thermoelectric Materials and Devices #Chalcogenide Semiconductor Thin Films #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Semiconductor materials and interfaces
paper · pdf · doi:10.48550/arxiv.2508.08988
openalex publication_date 2025/08/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Copper-based chalcopyrite semiconductors have attracted sustained interest owing to their promising thermoelectric (TE) performance, yet the microscopic origins of their TE behavior remain incompletely understood. Here, we systematically investigate the TE properties of CuMX2 (M= Al, Ga, and In; X= S, Se, and Te) using first-principles calculations. For p-type doping, the calculated electrical conductivities (σ), hole mobilities (μ), Seebeck coefficients (S), and power factors (PFs) of CuGaTe2 and CuInTe2 show excellent agreement with experimental data. At fixed temperature and hole concentration, as X varies from S to Te, the hole mobility increases markedly due to progressively weaker polar--optical--phonon scattering, reflecting the reduced ionic contribution to the dielectric response in compounds with heavier chalcogens. Combined with smaller transport effective masses, CuMTe2 compounds therefore exhibit high σ and large PFs. Across the CuMX2 family, the anomalously lower κL of CuMSe2 relative to CuMTe2 arises primarily from enhanced three-phonon scattering at low-frequency region. For a given M, CuMS2 displays the steepest temperature-induced decrease in κL and attains a smaller κL than CuMSe2 and CuMTe2 at 800~K. Given the low band degeneracy and comparatively modest hole mobilities of CuMX2 compounds, the most effective routes to further improve their TE performance are to enhance σ and reduce κL through doping.