Metal–insulator transition in variably doped (Bi1−xSbx)2Se3 nanosheets

摘要: Topological insulators are novel quantum materials with metallic surface transport but insulating bulk behavior. Often, topological dominated by contributions due to defect induced carriers, making it difficult isolate the more interesting characteristics. Here, we report synthesis and characterization of nanosheets a insulator Bi2Se3 variable Sb-doping levels control electron carrier density (Bi1−xSbx)2Se3 thin films thickness less than 10 nm prepared epitaxial growth on mica substrates in vapor setup. The introduction Sb effectively suppresses room temperature from ∼4 × 1013 cm−2 pure (x = 0) ∼2 1012 at x ∼ 0.15, while maintaining At ≳ ∼0.20, metal–insulator transition (MIT) is observed, indicating that system has transformed into an which conduction blocked. In agreement observed MIT, Raman spectroscopy reveals emergence vibrational modes arising Sb–Sb Sb–Se bonds high concentrations, confirming appearance Sb2Se3 crystal structure sample. These results suggest nanostructured chalcogenide controlled doping can be tunable platform for fundamental studies electronic applications systems.