Abstract Based on the first-principles calculations, we investigated the thermal expansion and related vibrational properties of monolayer α-Se and binary compounds α-TeSe2. The effect of binary compounds on thermal expansion properties is explored theoretically. We find the two monolayers show totally positive thermal expansion from 0 to 500 K. The linear thermal expansion coefficients are close to each other below 300 K. However, they are 3.5 and 2.5 × 10−5 K−1 for α-Se and α-TeSe2 at 500 K, showing much larger thermal expansion of the former. It can be attributed to the weaker Te–Se bond in α-TeSe2. Moreover, the phonon spectra, mode Gruneisen parameters, macroscopic Gruneisen parameters, and the contributions of phonon modes to total thermal expansion at different temperature are investigated detailed, in order to explore the underlying physical mechanisms of thermal expansion.

中文翻译：

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基于第一性原理计算的α-Se和α-TeSe2的热膨胀和振动特性

摘要 基于第一性原理计算，我们研究了单层 α-Se 和二元化合物 α-TeSe2 的热膨胀和相关振动特性。从理论上探讨了二元化合物对热膨胀性能的影响。我们发现这两个单层在 0 到 500 K 之间表现出完全正热膨胀。线性热膨胀系数在 300 K 以下彼此接近。然而，对于 α-Se 和 α，它们分别为 3.5 和 2.5 × 10−5 K−1 -TeSe2 在 500 K 时，显示前者的热膨胀大得多。这可以归因于 α-TeSe2 中较弱的 Te-Se 键。此外，详细研究了声子光谱、模式 Gruneisen 参数、宏观 Gruneisen 参数以及声子模式对不同温度下总热膨胀的贡献，