Thickness dependence of conductivity in Bi₂Se₃ topological insulator

The electrical resistivity of thin films of a topological insulator of Bi₂Se₃ with a thickness of 10 nm to 75 nm, single crystal of Bi₂Se₃ with thickness of 0.65 mm in the temperature range from 4.2 to 300 K was measured. A size effect in the electrical conductivity of Bi₂Se₃ films was observed, i.e. linear dependence of the conductivity of the sample on its inverse thickness. It was suggested that similar effects should be observed in other TIs and systems with non-uniform distribution of direct current over the cross section of the sample.