Evaluation of thermal conductivity of Mg2Si under high pressure via periodic heating in a multi-anvil system

Y Mori and Y Akimoto and R Okami and T Yoshino and Y Shuseki and A Masuno, JAPANESE JOURNAL OF APPLIED PHYSICS, 64, 12SP09 (2025).

DOI: 10.35848/1347-4065/ae202f

We developed a high-pressure measurement technique for evaluating the thermal conductivity of thermoelectric silicides using a periodic heating method in a six-axis multi-anvil press. By employing a dual- heater system and four pairs of thermocouples, we achieved simultaneous access to temperature oscillations from both ends of the sample, enabling precise determination of thermal diffusivity under pressure. Experiments on Al-doped Mg2Si were conducted at 1.0 GPa in the effective temperature range of 337-562 K, derived from thermocouple readings inside the pressure cell (corresponding to control temperatures of 373-873 K). The obtained thermal conductivity decreased monotonically with increasing temperature, consistent with phonon-dominated heat transport. The results are in good agreement with molecular dynamics simulations based on the Green-Kubo formalism, demonstrating that the present method provides a reliable platform for evaluating thermal transport properties of thermoelectric materials under high pressure.

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