Ultra-low lattice thermal conductivity has long been a requirement for the high thermoelectric properties of materials. In this work, the novel 1T-Au6Se2 monolayer was obtained by introducing Au6 clusters into the selenide monolayer, and its electrical and thermal transport characteristics are investigated using first-principles computations supplemented with semi-classical Boltzmann transport theory. The calculation shows that the 1T-Au6Se2 monolayer exhibits ultra-low lattice thermal conductivity and excellent thermoelectric properties owing to its low phonon frequency, group velocity, and extremely strong anharmonicity. Based on strain engineering from 0% to 2%, the lattice thermal conductivity further reduces by restricting the thermal transport on the premise of maintaining outstanding electrical transport properties in the p-type doped system. Thence, the value of ZT for the p-type system increases nearly by 70% compared with the non-stressed state at 700 K. Our investigation indicates the ultra-low thermal conductivity and high ZT of the 1T-Au6Se2 monolayer that might be prepared in the lab, providing new insights into enhancing the thermoelectric performance of the material in the future.
New, stable stoichiometries in Be-P systems are investigated up to 100 GPa by the CALYPSO structure prediction method. Along with the BeP2-I41/amd structure, we identify two novel compounds of Be3P2-P-421m and Be3P2-C2/m. It should be noted that the Be-P compounds are predicted to be energetically unfavorable above 40 GPa. As can be seen, interesting structures may be experimentally synthesizable at modest pressure. Our results indicate that at 33.2 GPa, the most stable ambient-pressure tetragonal Be3P2-P-421m transitions to the monoclinic Be3P2-C2/m structure. Moreover, the predicted Be3P2-P-421m and Be3P2-C2/m phases are energetically favored compared with the Be3P2-Ia-3 structure synthesized experimentally. Electronic structure calculations reveal that BeP2-I41/amd, Be3P2-P-421m, and Be3P2-C2/m are all semiconductors with a narrow band gap. The present findings offer insight and guidance for exploration toward further fundamental understanding and potential applications in the semiconductor field.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.