Realization of Fine‐Tuning the Lattice Thermal Conductivity and Anharmonicity in Layered Semiconductors via Entropy Engineering

Abstract

AbstractEntropy engineering is widely proven to be effective in achieving ultra‐low thermal conductivity for well‐performed thermoelectric and heat management applications. However, no strong correlation between entropy and lattice thermal conductivity is found until now, and the fine‐tuning of thermal conductivity continuously via entropy‐engineering in a wide entropy range is still lacking. Here, a series of high‐entropy layered semiconductors, Ni1−x(Fe0.25Co0.25Mn0.25Zn0.25)xPS3, where 0 ≤ x < 1, with low mass/size disorder is designed. High‐purity samples with mixing configuration entropy of metal atomic site in a wide range of 0–1.61R are achieved. Umklapp phonon‐phonon scattering is found to be the dominating phonon scattering mechanism, as revealed by the linear T−1 dependence of thermal conductivity. Meanwhile, fine tuning of the lattice thermal conductivity via continuous entropy engineering at metal atomic sites is achieved, in an almost linear dependence in middle‐/high‐ entropy range. Moreover, the slope of the κ ‐ T−1 curve reduces with the increase in entropy, and a linear response of the reduced Grüneisen parameter is revealed. This work provides an entropy engineering strategy by choosing multiple metal elements with low mass/size disorder to achieve the fine tuning of the lattice thermal conductivity and the anharmonic effect.