TDDFT-MD simulation of ultrafast carrier decay in nanotubes: Dependence on the lattice temperature

Abstract Submitted to the ;

TDDFT-MD simulation of ultrafast carrier decay in nanotubes: Dependence on the lattice temperature

Yoshiyuki Miyamoto, Angel Rubio*, and David Tomanek**

Fundamental and Environmental Res. Labs. NEC, *Dpto. Fisica de Materiales, Facultad de Quimicas, U. Pais Vasco, Centro Mixto CSIC-UPV/EHU and Donostia International Physics Center (DIPC), and **Physics and Astronomy Department, Michigan State Univ.
Contact e-mail: y-miyamoto@ce.jp.nec.com

Realization of electronic and opto-electronic nanoscale devices isone of the most challenging subjects in nanotube applications.Carrier lifetime is crucial for optimizing the clock frequenciesof the devices. Experimental observations using femtosecond laserspectroscopy [1,2] suggested a rapid carrier decay in nanotubes,which was attributed to electron-electron coupling in the earlystage and electron-phonon coupling at a later stage. Recenttheoretical treatment of electron-phonon coupling [3] necessitates　the inclusion of electron-electron coupling.

We present a microscopic study of hot carrier dynamics in vibrating carbon nanotubes. Using the computer code FPSEID [4], which couples time-dependent density functional simulations with classical molecular dynamics, we are able to monitor both types of coupling simultaneously in real time. We investigate the electron-electron coupling in early stage by monitoring the time dependence of the potential energy of the lattice. In order to clarify the electron-phonon coupling contribution, we further investigate the dependence of the lattice dynamics on the initial lattice temperature.

References:
[1] T. Hertel, and G. Moos, Phys. Rev. Lett. 84, 5002 (2000).
[2] M. Ichida, et al., Physica B 323, 237 (2002).
[3] See, for example, J. Jiang et al., Phys. Rev. B71, 45417 (2005).
[4] O. Sugino and Y. Miyamoto, Phys. Rev. B59, 2579 (1999); ibid, Phys. Rev. B66, 89901(E) (2002).

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