Thermal relaxation in titanium nanowires: signatures of inelastic electron-boundary scattering in heat transfer

摘要: We have employed noise thermometry for investigations of thermal relaxation between the electrons and substrate in nanowires patterned from 40-nm-thick titanium film on top silicon wafers covered by a native oxide. By controlling electronic temperature $T_e$ Joule heating at base dilution refrigerator, we probe electron-phonon coupling boundary resistance temperatures $T_e= 0.5 - 3$ Kelvin. Using regular $T^5$-dependent clean metals $T^4$-dependent interfacial heat flow, deduce small contribution direct energy transfer to phonons due inelastic electron-boundary scattering.