Negative resistance characteristics in tunneling experiments on metallic samples

Abstract

Scanning tunneling microscopy experiments on specific semiconducting samples show negative resistance characteristics. It is predicted that similar behavior can be achieved on metallic samples. The requirement for those samples is the existence of a bulk band gap for electron momentum perpendicular to sample surface. Calculations for a tip-vacuum-Ni(100) junction have been performed. In this system, negative resistance characteristics arise due to the presence of localized surface barrier states. Another property of those systems is that negative resistance disappears with increasing temperature.