Image-potential-induced states at metal surfaces

TL;DR

This paper reviews the theory and significance of image-potential-induced surface states at metal surfaces, emphasizing their origin from the long-range image potential and their impact on surface physics research.

Contribution

It provides a comprehensive discussion of the theoretical understanding of image states and their role in surface physics, highlighting developments since their discovery in the 1980s.

Findings

Identification of image states as bound states due to the image potential

Explanation of the long-range nature of the image potential

Historical overview of research developments in surface states

Abstract

The unequivocal observation in the early 1980s of a new class of unnocupied surface states that are bound to the vacuum level of a variety of metal surfaces has led over the last two decades to an active area of research in condensed-matter and surface physics. We discuss the key ingredients of the theory of these so-called image states, which have their origin in the long range nature of the image potential outside a solid.