Subthreshold Carrier-LO Phonon Dynamics in Semiconductors with Intermediate Polaron Coupling: A Purely Quantum Kinetic Relaxation Channel

M. Betz; G. Göger; A. Laubereau; P. Gartner; L. Bányai; H. Haug; K. Ortner; C. R. Becker; A. Leitenstorfer

doi:10.1103/PhysRevLett.86.4684

Subthreshold Carrier-LO Phonon Dynamics in Semiconductors with Intermediate Polaron Coupling: A Purely Quantum Kinetic Relaxation Channel

M. Betz, G. Göger, A. Laubereau, P. Gartner, L. Bányai, H. Haug, K. Ortner, C. R. Becker, and A. Leitenstorfer

Phys. Rev. Lett. 86, 4684 – Published 14 May 2001

Abstract

Femtosecond transmission spectra of highly polar CdTe are compared to more covalent GaAs contrasting semiclassical kinetics with two-time quantum kinetics based on the Dyson equation. Nonequilibrium heavy holes in CdTe show ultrafast energy redistribution via the Fröhlich mechanism even if photoexcited below the LO phonon energy. This subthreshold relaxation is a genuine quantum kinetic effect. It gains importance if the polaron self-energy is comparable to the phonon energy. Conservation of the free-particle energies is not required under these conditions.

Received 25 October 2000

DOI:https://doi.org/10.1103/PhysRevLett.86.4684

Authors & Affiliations

M. Betz¹, G. Göger¹, A. Laubereau¹, P. Gartner^2,3, L. Bányai², H. Haug², K. Ortner⁴, C. R. Becker⁴, and A. Leitenstorfer¹

¹Physik-Department E11, Technische Universität München, D-85748 Garching, Germany
²Institut für theoretische Physik, J. W. Goethe Universität, D-60054 Frankfurt am Main, Germany
³National Institute for Physics of Materials, Bucharest, Romania
⁴Physikalisches Institut, Universität Würzburg, D-97074 Würzburg, Germany