The thermoelectric performance of SnSe strongly depends on its low-energy electron band structure that provides high density of states in a narrow energy window due to the multi-valley valence band maximum (VBM). Angle-resolved photoemission spectroscopy measurements, in conjunction with first-principles calculations, reveal that the binding energy of the VBM of SnSe is tuned by the population of Sn vacancy, which is determined by the cooling rate during the sample growth. The VBM shift follows precisely the behavior of the thermoelectric power factor, while the effective mass is barely modified upon changing the population of Sn vacancies. These findings indicate that the low-energy electron band structure is closely correlated with the high thermoelectric performance of hole-doped SnSe, providing a viable route toward engineering the intrinsic defect-induced thermoelectric performance via the sample growth condition without an additional ex-situ process.

中文翻译：

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通过控制空位数量增强 SnSe 的热电性能

SnSe 的热电性能很大程度上取决于其低能电子能带结构，该结构由于多谷价带最大值 (VBM) 而在窄能量窗口中提供高态密度。角分辨光电子能谱测量与第一原理计算相结合，揭示了 SnSe 的 VBM 的结合能是通过 Sn 空位的数量来调节的，而 Sn 空位的数量是由样品生长过程中的冷却速率决定的。VBM 的变化精确地遵循热电功率因数的行为，而有效质量在改变 Sn 空位数量时几乎没有改变。这些发现表明，低能电子能带结构与空穴掺杂 SnSe 的高热电性能密切相关，