Temperature dependence of electrical and thermal conduction in single silver nanowire

Silver nanowires have great application potential in fields like flexible electronic devices, solar cells and transparent electrodes. It is critical and fundamental to study the thermal and electrical transport properties in a single silver nanowire. In this work, the thermal and electrical transport in an individual silver nanowire is characterized down to 35 K with the steady state electro-thermal technique. The results indicate that, at room temperature, the electrical resistivity increases by around 4 folds compared from that of its bulk counterpart. After fitting the temperature dependent electrical resistivity curves with the Bloch-Gr\"uneisen formula, the Debye temperature (151 K) of the silver nanowire is found 36% lower than that (235 K) of bulk silver, confirming strong phonon softening. The thermal conductivity is reduced by 55% compared with that of its bulk counterpart at room temperature and this reduction becomes larger as the temperature goes down. To explain the opposite trends of thermal conductivity (\k{appa}) ~ temperature (T) of silver nanowire and bulk silver, a unified thermal resistivity is used to elucidate the electron scattering mechanism. A large residual unified thermal resistivity for the silver nanowire is observed while that of the bulk silver is almost zero. The same trend of variation against T indicates that the silver nanowire and bulk silver share the same phonon-electron scattering mechanism. Additionally, due to phonon-assisted electron energy transfer across the grain boundaries, the Lorenz number of the silver nanowire is found much larger than that of bulk silver and decreases with decreasing temperature.