Probing nanoscale solids at thermal extremes

We report a novel nanoscale thermal platform compatible with extreme temperature operation and real-time high-resolution transmission electron microscopy. Applied to multiwall carbon nanotubes, we find atomic-scale stability to 3200 K, demonstrating that carbon nanotubes are more robust than graphite or diamond. Even at these thermal extremes, nanotubes maintain 10% of their peak thermal conductivity and support electrical current densities similar to 2x10(8) A/cm(2). We also apply this platform to determine the diameter dependence of the melting temperature of gold nanocrystals down to three nanometers.