Observation of resonant tunneling effects on narrow stripe structure of the 8OCB liquid crystal deposited on the (0001) basal plane of highly oriented pyrolitic graphite by scanning tunneling spectroscopy

Scanning tunneling microscopy and spectroscopy are used to study the self-a ssembled 80CB liquid crystal deposited on the (0001) basal plane of highly oriented pyrolitic graphite. In order to minimize the molecule-molecule int eractions the single narrow stripe structures of liquid crystal are created and investigated. The I/V measurements recorded over a single narrow strip e show distinct negative resistance regions or nearly flat regions of the t unneling current. This can be a explained by the resonant tunneling model w hich includes tunneling via discrete energy levels of the molecule. The Cou lomb blockade effect is excluded as a mechanism for the occurrence of nearl y flat regions on the I/V characteristics. (C) 2000 Elsevier Science B.V. A ll rights reserved.