We found a large thermoelectric figure of merit in the hexagonal phase of 2D selenium and tellurium from first‐principles calculations. The hexagonal phase (α ) is obtained from three atomic layers truncated along the [001] direction of trigonal Te and Se bulk in the equilibrium structure. We found the α ‐Se structure dynamically stable. The calculated electronic structures of α ‐Se and α ‐Te show interesting semiconductor character for both electronic and optoelectronic applications. Furthermore, the obtained elastic properties show that hexagonal tellurene is a softer material than selenene. The thermoelectric figure of merit for hexagonal 2D phase (∼1.0) is larger than those reported for the tetragonal 2D phase (∼0.75) of selenium and tellurium. Additionally, the computed electrical and phonon transport parameters indicate that selenene and tellurene are promising thermoelectric materials; both offer an alternative to recovering residual heat and transforming it into electricity.

中文翻译：

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二维硒和碲六方相的大型热电性能因数

通过第一性原理计算，我们发现了二维硒和碲六方相中的一个较大的热电性能因数。六方相（α）是从在平衡结构中沿三角形Te和Se体的[001]方向截断的三个原子层获得的。我们发现α- Se结构是动态稳定的。计算的α- Se和α电子结构‐Te在电子和光电应用中都表现出有趣的半导体特性。此外，所获得的弹性性质表明，六边形碲烯比硒烯更软。六角形二维相（〜1.0）的热电品质因数大于硒和碲的二维二维相（〜0.75）的热电品质因数。此外，计算得出的电和声子输运参数表明，硒和碲是有前途的热电材料；两者都提供了回收余热并将其转化为电能的替代方法。