Time-Resolved Imaging of Negative Differential Resistance on the Atomic Scale

TL;DR

This study uses advanced time-resolved microscopy and modeling to understand negative differential resistance at the atomic scale, revealing its many-body nature and capturing its spatial and temporal dynamics.

Contribution

It introduces a novel all-electronic time-resolved STM technique combined with a Green's function model to study electron dynamics of a dangling bond on silicon.

Findings

Negative differential resistance is a many-body phenomenon.

Measured all relevant time constants of electron capture.

Produced atomically resolved nanosecond images of the effect.

Abstract

Negative differential resistance remains an attractive but elusive functionality, so far only finding niche applications. Atom scale entities have shown promising properties, but viability of device fabrication requires fuller understanding of electron dynamics than has been possible to date. Using an all-electronic time-resolved scanning tunneling microscopy technique and a Green's function transport model, we study an isolated dangling bond on a hydrogen terminated silicon surface. A robust negative differential resistance feature is identified as a many body phenomenon related to occupation dependent electron capture by a single atomic level. We measure all the time constants involved in this process and present atomically resolved, nanosecond timescale images to simultaneously capture the spatial and temporal variation of the observed feature.