Semiconductor Physics, Quantum Electronics & Optoelectronics. 2017. V. 20, N 2. P. 185-190. DOI: https://doi.org/10.15407/spqeo20.02.185 London forces in highly oriented pyrolytic graphite

Abstract

Abstract. Surface of highly oriented pyrolytic graphite with terrace steps was studied using scanning tunneling microscopy with high spatial resolution. Spots with positive and negative charges were found in the vicinity of the steps. Values of the charges depended both on the microscope needle scan velocity and on its motion direction. The observed effect was theoretically explained with account of London forces that arise between the needle tip and the graphite surface. In this scheme, a terrace step works as a nanoscale diode for surface electric currents.