Influence of Phonon dimensionality on Electron Energy Relaxation

Abstract

We studied experimentally the role of phonon dimensionality on electron-phonon (e-p) interaction in thin copper wires evaporated either on suspended silicon nitride membranes or on bulk substrates, at sub-Kelvin temperatures. The power emitted from electrons to phonons was measured using sensitive normal metal-insulator-superconductor (NIS) tunnel junction thermometers. Membrane thicknesses ranging from 30 nm to 750 nm were used to clearly see the onset of the effects of two-dimensional (2D) phonon system. We observed for the first time that a 2D phonon spectrum clearly changes the temperature dependence and strength of the e-p scattering rate, with the interaction becoming stronger at the lowest temperatures below $\sim$ 0.5 K for the 30 nm membranes.

Phys. Rev. Lett. in press

References in corpus (2)

• Heat transport in ultra-thin dielectric membranes and bridges
• Inelastic relaxation and noise temperature in S/N/S junctions

Cited by in corpus (4)

• Phonon cooling of nanomechanical beams with tunnel junctions
• Electronic cooling of a submicron-sized metallic beam
• Effects of charging energy on SINIS tunnel junction thermometry
• Cooling of suspended nanostructures with tunnel junctions