Electron-phonon coupling and longitudinal mechanical-mode cooling in a metallic nanowire

TL;DR

This paper theoretically explores how electron-phonon interactions in a narrow metallic nanowire enable cooling of longitudinal mechanical modes via electronic tunnel refrigeration, with implications for experimental nanomechanics.

Contribution

It provides explicit theoretical analysis of electron-phonon coupling in 1D phonon modes with 3D electrons, demonstrating mechanical mode cooling feasibility.

Findings

Longitudinal vibrational modes can be cooled below bath temperature.

High mechanical quality factors are essential for effective cooling.

Results are applicable to realistic experimental setups.

Abstract

We investigate electron-phonon coupling in a narrow suspended metallic wire, in which the phonon modes are restricted to one dimension but the electrons behave three-dimensionally. Explicit theoretical results related to the known bulk properties are derived. We find out that longitudinal vibration modes can be cooled by electronic tunnel refrigeration far below the bath temperature provided the mechanical quality factors of the modes are sufficiently high. The obtained results apply to feasible experimental configurations.