Temperature Dependence of Electron to Lattice Energy-Transfer in Single-Wall Carbon Nanotube Bundles

Gunnar Moos¹, Roman Fasel², and Tobias Hertel¹

¹Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
²EMPA Dübendorf, Überlandstr. 129, 8600 Dübendorf, Switzerland

The electron-phonon coupling strength in single-wall carbon nanotube (SWNT) bundles has been studied directly in the time-domain by femtosecond time-resolved photoelectron spectroscopy. We have measured the dependence of H(T_e,T_l), the rate of energy-transfer between the electronic system and the lattice as a function of electron and lattice temperatures T_e and T_l . The experiments show that H scales approximately with the 5^th power of the electron- and lattice-temperatures. The results can be related to the e-ph mass enhancement parameter l. The experimentally obtained value for l/Q², where Q is the Debye temperature, suggests that e-ph scattering times at the Fermi level of SWNT bundles can be exceptionally long, exceeding 1.5 ps at room temperature.