Thermal resistance of metal nanowire junctions in the ballistic regime

In the ballistic regime of transport, we derive the thermal resistance of metal nanowires connected to two heat baths. We find that the thermal resistances for any metal nanowire remain in a narrow and temperature-dependent interval between 0.447/$T$ and 14/$T$ ${\mathrm{m}}^{2}$ K/W. For cross-section edges larger than 20 nm, the thermal resistance can actually be estimated from $\frac{{R}_{0}}{(3\ensuremath{\pi}{n}_{V}^{2}){}^{3}}$, where ${R}_{0}$ is the quantum of resistance and ${n}_{V}$ refers to the electron density. This prediction yields a contact resistance one order of magnitude larger than the one of previous estimations. Significant consequences for application fields such as nanoelectronics, where nanowire sizes involve ballistic transport, are expected.