Why holes are not like electrons. II. The role of the electron-ion interaction

TL;DR

This paper explores the fundamental differences between electrons and holes caused by electron-ion interactions, emphasizing that holes are more dressed than electrons, and suggests superconductivity results from carriers 'undressing' from both interactions.

Contribution

It introduces the idea that electron-ion interactions cause a fundamental difference between electrons and holes, paralleling electron-electron effects, and links this to the mechanism of superconductivity.

Findings

Holes are more dressed than electrons due to electron-ion interactions.

Superconductivity involves 'undressing' carriers from both electron-electron and electron-ion interactions.

Observable consequences arise from the undressing process.

Abstract

In recent work, we discussed the difference between electrons and holes in energy band in solids from a many-particle point of view, originating in the electron-electron interaction, and argued that it has fundamental consequences for superconductivity. Here we discuss the fact that there is also a fundamental difference between electrons and holes already at the single particle level, arising from the electron-ion interaction. The difference between electrons and holes due to this effect parallels the difference due to electron-electron interactions: {\it holes are more dressed than electrons}. We propose that superconductivity originates in 'undressing' of carriers from $both$ electron-electron and electron-ion interactions, and that both aspects of undressing have observable consequences.