  The thermal properties of a suspended metallic single-wall carbon nanotube
(SWNT) are extracted from its high-bias (I-V) electrical characteristics over
the 300-800 K temperature range, achieved by Joule self-heating. The thermal
conductance is approximately 2.4 nW/K and the thermal conductivity is nearly
3500 W/m/K at room temperature for a SWNT of length 2.6 um and diameter 1.7 nm.
A subtle decrease in thermal conductivity steeper than 1/T is observed at the
upper end of the temperature range, which is attributed to second order
three-phonon scattering between two acoustic modes and one optical mode. We
discuss sources of uncertainty and propose a simple analytical model for the
SWNT thermal conductivity including length and temperature dependence.
