Local surface conductivity of single crystalline Bi2Te3 (0001).

Samples of the topological insulator n-Bi2Te3 (0001) have been studied in air by means of atomic force microscopy. The possibility to increase the sample conductivity by five or more orders of magnitude has been found. Bulk single crystalline films (few microns thick) and microflakes (∼100 nm thick) are compared. Unlike the local effect on the bulk film, the entire surface of the microflake can be switched to the conductive state. Besides, when switched, the conductivity of the microflake is usually higher by orders of magnitude than that of the bulk film. A possible mechanism for the effect is discussed. [ABSTRACT FROM AUTHOR]