Lattice Thermal Transport in the Homogeneous Cage‐Like Compounds Cu₃VSe₄ and Cu₃NbSe₄: Interplay between Phonon‐Phase Space, Anharmonicity, and Atomic Mass

Abstract

Understanding the correlation between crystal structure and thermal conductivity in semiconductors is very important for designing heat-transport-related devices, such as high-performance thermoelectric materials and heat dissipation in micronano-scale devices. In this work, the lattice thermal conductivity (k L ) of the cage-like compounds Cu 3 VSe 4 and Cu 3 NbSe 4 was investigated by experimental measurements and first-principles calculations. The experimental k L of Cu 3 NbSe 4 is approximately 25 % lower than that of Cu 3 VSe 4 at 300 K. The relevant important physical parameters, including the sound velocity, heat capacity, weighted phonon phase space (W), and thirdorder force constants along with atomic mass were theoretically analyzed. It is found that W is the dominant parameter in determining the k L , and the other factors only play a minor role. The physical origin is the relatively "soft" lattice of Cu 3 NbSe 4 with heavier atomic mass. This research provides deep insight into the correlation between the thermal conductivity and crystal structure and paves the way for discovering highperformance thermal management device and thermoelectric materials with intrinsically low k L .

Solution-phase controlled synthesis of Cu3NbSe4 nanocrystals for optoelectronic applications

“…Alternatively, sulvanite-type Cu 3 MX 4 (M = V, Nb, and Ta; X = S, Se, and Te) compounds have been regarded as promising photoabsorbers for the conversion of solar energy into electricity and fuels due to their extraordinary properties, including tunable bandgap energy, high optical absorption coefficient, and readily available and comparatively abundant elements. [22][23][24][25][26][27][28][29] For example, Ikeda et al reported that Cu 3 Nb 1−x V x S 4 shows promise for application in photocatalytic H 2 evolution under visible light irradiation. 30 Liu et al reported that Cu 3 VS 4 nanocrystals can be tuned from plasmonic-like to excitonic simply via coating with CdS shells.…”