Nanoscale Probing of Local Electrical Characteristics on MBE-Grown Bi2Te3 Surfaces under Ambient Conditions

作者：Macedo Rita J; Harrison Sara E; Dorofeeva Tatiana S; Harris James S; Kiehl Richard A^*

来源：Nano Letters, 2015, 15(7): 4241-4247.

DOI：10.1021/acs.nanolett.5b00542

• Bismuth telluride
• topological insulators
• van der Waals epitaxy
• molecular beam epitaxy
• atomic force microscopy

The local electrical characteristics on the surface of MBE-grown Bi2Te3 are probed under ambient conditions by conductive atomic force microscopy. Nanoscale mapping reveals a 10-100x enhancement in current at step-edges compared to that on terraces. Analysis of the local current voltage characteristics indicates that the transport mechanism is similar for step-edges and terraces. Comparison of the results with those for control samples shows that the current enhancement is not a measurement artifact but instead is due to local differences in electronic properties. The likelihood of various possible mechanisms is discussed. The absence of enhancement at the step-edges for graphite terraces is consistent with the intriguing possibility that spin orbit coupling and topological effects play a significant role in the step-edge current enhancement in Bi2Te3.

• 出版日期2015-7