Observation of phonon structure in electron density of states of a normal metal

¹ Department of Physics and Astronomy, McMaster University Hamilton, Ontario, Canada, L8S 4M1
² Department of Physics, University of Alberta - Edmonton, Alberta, Canada, T6J 2J1

Received: 29 April 2005
Accepted: 5 July 2005

Abstract

Within standard treatments of the interacting electron-phonon system the electron density of states (EDOS) shows no sign of the phonons when the system is in the normal state. On the other hand, emergence of a fine energy scale in the superconducting state makes the phonons readily observable in the EDOS and other spectroscopic quantities. Here we wish to re-examine the conditions under which phonon structure might be present in the normal state. Accounting for a finite, i.e. non-infinite, electronic bandwidth results in easily distinguishable phonon structure in the EDOS. We argue that for narrow-band metals, the resolution of photoemission spectroscopy is sufficient for resolving these structures. Manifestations of finite-band effects in are discussed.