Observation of negative differential resistance on View the MathML source using STM

We investigated the initial stage of Ag adsorption on the Si(100) surface at low temperature. From STM images at − 1 and + 1 V, occupied and unoccupied orbitals of neighboring two Ag sites are uncoupled and coupled, respectively. We observed another adsorption structure at low temperature in comparison with the room temperature. We also measured the I-V characteristics over Ag sites which indicate two distinct peaks of negative differential resistance in the empty state. The mechanism behind this phenomenon is attributed to the localized surface states of Ag within the Si bulk band gap.