Hostname: page-component-76fb5796d-wq484 Total loading time: 0 Render date: 2024-04-26T17:33:16.427Z Has data issue: false hasContentIssue false
  • English
  • Français

Phonon Bottleneck Effect in Organic Molecules

Published online by Cambridge University Press:  31 January 2011

S. Bandyopadhyay  and
Bhargava Kanchibotla
S. Bandyopadhyay
Affiliation:
sbandy@mail2.vcu.edu, Virginia Commonwealth University, Electrical and Computer Engineering, 601 W. Main Street, Richmond, Virginia, 23284, United States, 804-827-6275, 804-827-0006
Bhargava Kanchibotla
Affiliation:
kanchibotlbv@vcu.edu, Virginia Commonwealth University, Electrical and Computer Engineering, Richmond, Virginia, United States
Get access

Abstract

We have measured the ensemble averaged transverse spin relaxation time T2* (associated with g = 4 resonance) in bulk powders of the organic molecule Alq3, and in samples containing 1-2 molecules confined in nanocavities of dimension ˜ 2 nm. Both T2* times are strongly temperature dependent indicating that they are determined by phonon-mediated spin relaxation. Interestingly, the T2* time in nanocavities is ˜2.5 times longer than in bulk powder over a wide temperature range. The longer T2* in the nanocavity is evidence of weakened electron-phonon interaction. We believe that electron-phonon interaction is suppressed because the cavity confines phonons and discretizes the phonon modes and phonon energies. As a result, the chances of a phonon induced (inelastic) spin relaxation event are reduced owing to the need to conserve energy in the relaxation process. This is a novel “phonon bottleneck effect” that to our knowledge has not been previously reported.

Keywords

electron spin resonanceelectron-phonon interactionsorganic
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1172: Symposium T – Nanoscale Heat Transport–From Fundamentals to Devices , 2009 , 1172-T02-04
Copyright
Copyright © Materials Research Society 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1 Benisty, H. Sotomayor-Torres, C. M. and Weisbuch, C. Phys. Rev. B, 44, 10945 (1991).Google Scholar
2 Rocha, A. Garcia-Suarez, V. M., Bailey, S. W. Lambert, C. J. Ferrar, J. and Sanvito, S. Nature Mater., 4, 335 (2005).Google Scholar
3 Reiger, P. H. Electron Spin Resonance: Analysis and Interpretation (The Royal Society of Chemistry, Cambridge, 2007).Google Scholar
4 Huang, G. S. Hu, X. L. Xie, Y. Kong, F. Zhang, Z. Y. Siu, G. G. and Chu, P. K. Appl. Phys. Lett., 87, 151910 (2005) and references therein.Google Scholar
5 Bandyopadhyay, S. et al., Nanotechnology, 7, 360 (1996).Google Scholar
6 Masuda, H. and Satoh, M. Jpn. J. Appl. Phys., Part 2, 35, L126 (1996).Google Scholar
7 Macdonald, D. D. J. Electrochem. Soc., 140, L27 (1993).Google Scholar
8 Ono, S.. Ichinose, H. and Masuko, N. J. Electrochem. Soc., 138, 3705 (1991).Google Scholar
9 Grecu, M. N. Mirea, A. Ghica, C. Colle, M. and Schwoerer, M. J. Phys: Condens. Matter, 17, 6271 (2005) and references therein.Google Scholar
10 Kanchibotla, B. Pramanik, S. Bandyopadhyay, S. and Cahay, M. Phys. Rev. B, 78, 193306 (2008).Google Scholar
11 Sanvito, S. Nature Mater., 6, 803 (2007).Google Scholar
12 Nishiguchi, N. Phys. Rev. B, 52, 5279 (1995).Google Scholar
13 Svizhenko, A. Balandin, A. Bandyopadhyay, S. and Stroscio, M. A. Phys. Rev. B, 57, 4687 (1998).Google Scholar