Role of the electric field in surface electron dynamics above the vacuum level

TL;DR

This study uses scanning tunneling spectroscopy to investigate how electric fields influence the behavior of hot electrons on a copper surface, revealing interference patterns and broadening mechanisms of field emission resonances.

Contribution

It provides new insights into the role of electric fields in surface electron dynamics and characterizes broadening mechanisms of FERs on Cu(100) surfaces.

Findings

Isotropic electron interference patterns around defects within surface band gaps

Broad wave vector distribution due to lateral acceleration in tip-induced potential

Relation between peak width and intrinsic line-width of FERs

Abstract

Scanning tunneling spectroscopy (STS) is used to study the dynamics of hot electrons trapped on a Cu(100) surface in field emission resonances (FER) above the vacuum level. Differential conductance maps show isotropic electron interference wave patterns around defects whenever their energy lies within a surface projected band gap. Their Fourier analysis reveals a broad wave vector distribution, interpreted as due to the lateral acceleration of hot electrons in the inhomogeneous tip-induced potential. A line-shape analysis of the characteristic constant-current conductance spectra permits to establish the relation between apparent width of peaks and intrinsic line-width of FERs, as well as the identification of the different broadening mechanisms.