Observation of Ballistic Thermal and Electrical Transport in Multi‐wall Carbon Nanotubes

We report thermal measurements on individual carbon nanotubes using a temperature sensing scanned microscope probe. An arc‐grown bundle of multi‐walled nanotubes (MWNTs) is mechanically attached to a thermal probe. The heat flow down individual MWNTs is recorded as a function of the temperature difference across them. Simultaneous measurements of thermal and electrical conductance are recorded. A study of the MWNTs size distribution using statistical methods on AFM images allowed us to model the available phonon channels. The size of the ballistic conductance steps observed at room temperature and the correlation between electrical and thermal conductance steps are discussed and we present the first evidence for ballistic transport of both phonons and electrons and in these tubes.