Lifetimes of Stark-shifted image states

TL;DR

This paper calculates how electrostatic Stark shifts in scanning tunneling microscopy reduce the lifetimes of electron image states at Cu(100) by increasing inelastic scattering channels and wave function overlap.

Contribution

It provides the first detailed GW approximation calculations of Stark-shifted image state lifetimes under typical tunneling conditions.

Findings

Lifetimes are significantly reduced by Stark shifts.

Higher energy shifts open more inelastic decay channels.

Wave function overlap increases inelastic scattering efficiency.

Abstract

The inelastic lifetimes of electrons in image-potential states at Cu(100) that are Stark-shifted by the electrostatic tip-sample interaction in the scanning tunneling microscope are calculated using the many-body GW approximation. The results demonstrate that in typical tunneling conditions the image state lifetimes are significantly reduced from their field-free values. The Stark-shift to higher energies increases the number of inelastic scattering channels that are available for decay, with field-induced changes in the image state wave function increasing the efficiency of the inelastic scattering through greater overlap with final state wave functions.