Giant Enhancement of Seebeck Coefficient by Deformation of Silicene Buckled Structure in Calcium‐Intercalated Layered Silicene Film

Abstract

Abstract 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 CaSi 2 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 CaSi 2 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 ≈3000 times larger power factor (≈40 μW cm −1 K −2 ) than that of the reported CaSi 2 film at room temperature. This result experimentally demonstrates that power factor can be greatly enhanced by deforming the silicene buckled structure.