Insensitivity of Sub-Kelvin Electron-Phonon Coupling to Substrate Properties
Jason M. Underwood, Peter J. Lowell, Galen C. O'Neil, Joel N. Ullom
We have examined the role of the substrate on electron-phonon coupling in normal metal films of Mn-doped Al at temperatures below 1 K. Normal metal-insulator-superconductor junctions were used to measure the electron temperature in thin metal films as a function of Joule heating power and phonon temperature. Theory suggests that the distribution of phonons available for interaction with electrons in thin metal films may depend on the acoustic properties of the substrate. Namely, that the electron- phonon coupling constant Σ would be larger on the substrate with smaller lattice moduli (smaller sound speed). In contrast, our results indicate that within experimental error, Σ is unchanged among the two acoustically distinct substrates used in our investigation.
, Lowell, P.
, O'Neil, G.
and Ullom, J.
Insensitivity of Sub-Kelvin Electron-Phonon Coupling to Substrate Properties, Physical Review Letters, [online], https://doi.org/10.1103/PhysRevLett.107.255504
(Accessed December 1, 2023)