Giant Enhancement of Seebeck Coefficient by Deformation of Silicene Buckled Structure in Calcium-Intercalated Layered Silicene Film
Giant Enhancement of Seebeck Coefficient by Deformation of Silicene Buckled Structure in Calcium-Intercalated Layered Silicene Film
复制标题
DOI：
10.1002/admi.202101752
复制
发表时间：
2021-11-25
影响因子：
5.4
通讯作者：
Nakamura, Yoshiaki
中科院分区：
文献类型：
--
作者：
Terada, Tsukasa;Uematsu, Yuto;Nakamura, Yoshiaki
具有变形屈曲结构的层状硅烯作为超越传统层状材料的下一代二维狄拉克热电材料引起了人们的极大兴趣。然而，调节硅烯中原子位置的困难阻碍了其实现。这项研究提出了一种通过控制插层原子来使层状硅烯中的屈曲结构变形的方法，这可以显着增强其热电性能。 Si(111)衬底上的外延CaSi2薄膜（Ca插层硅烯）中硅烯屈曲结构发生变形，这与插层Ca的组成有关。其中，改变了硅烯的屈曲高度。这种含有变形硅烯的CaSi2薄膜不仅表现出类金属的导电性，而且塞贝克系数比理论预测值大三倍，导致室温下的功率因数比报道的CaSi2薄膜高出约3000倍（约40 mu W cm(-1) K-2）。该结果通过实验证明，通过使硅烯屈曲结构变形可以大大提高功率因数。
Layered silicene with deformed buckled structure attracts great interest as a next generation 2D Dirac thermoelectric material beyond conventional layered materials. However, the difficulty of modulating atomic positions in silicene prevents its realization. This study proposes a method to deform buckled structure in layered silicene by controlling the intercalated atoms, which can dramatically enhance its thermoelectric properties. Silicene buckled structure is deformed in epitaxial CaSi2 thin films, Ca-intercalated layered silicenes, on Si(111) substrates, which is related to the composition of intercalated Ca. Therein, buckling height of silicene is changed. This CaSi2 film with deformed silicene exhibits not only metal-like electrical conductivity but also three times larger Seebeck coefficient than the theoretically predicted value, resulting in approximate to 3000 times larger power factor (approximate to 40 mu W cm(-1) K-2) than that of the reported CaSi2 film at room temperature. This result experimentally demonstrates that power factor can be greatly enhanced by deforming the silicene buckled structure.