<研究ノート>Bi₂Te₃超薄膜の電子構造と電気伝導

Abstract

We have investigated electronic structure and electrical conduction of ultrathin (111)-oriented Bi₂Te₃ films epitaxially grown on Si (111). Layer-by-layer growth of Bi₂Te₃ was confirmed by electronic band structure depending on the number of quintuple layers (QLs). In situ four-point probe conductivity measurements showed metallic conduction of the films at 1–5 QL. A large increase in conductivity from 1 to 2 QL is related to a bulk-like conduction band (CB) state. Although the partial occupation of the CB is attributed to antisite defects at the Bi site, scattering by the defects is expected to be insignificant because the CB electrons are localized at the Te atoms forming the van der Waals interface.