Estimation of tunneling-barrier width in scanning tunneling microscope from noise characteristics

A method is proposed for estimation of the potential-barrier width of the t unneling junction of a scanning tunneling microscope (STM). The method is b ased on measurement of the flutuations of the tunneling-barrier height and their correlation with the flicker noise of the tunneling current. Measurem ents with the STM feedback enabled and disabled are considered. Experimenta l results are presented for a tunnealing junction formed by a platinum-irid ium tip and a graphite specimen. The principal sources of experimental erro r are examined.