Dr Paul Kinsler. [Acknowledgements & Feedback]

This is part of a hyperlinked notes maze -- please read the index-file for important information about the nature and reliability of this document.

Scattering of electrons by optical modes in bulk semiconductors and quantum wells

Hot electrons in semiconductors: physics and devices, (Oxford 1998)

*copied*

This uses a continuum approach.

"Fortuitously, the typical transition wavector (in GaAs) is sufficiently large to also justify a treatment of the fields in the unretarded regime (Babiker-CR-1993)". This means we get a scalar potential for the EM-Field, and we can use QFT; but we then need to explicitly state boundary conditions.

hybrid-phonons are needed to explain Raman and micro-raman measurements in lattices and superlattices, and indeed for all things (unless we can approximate).

"The calculations of scattering rates based on the hybrid-phonon model have indeed led to marked differences in the contributions to scattering arising from individual hybrid-phonon branches when compared with the predictions of the DC-model and HD-model models. However, the total scattering rate arising from summing hybrid-phonon branch contributions differed little from that evaluated on the basis of the DC-model (37. Ridley-BZB-1996, 38. Ridley-ABZB-1997).

This is explained by a sum-rule (Mori-A-1989, Register-1992) -- which occurs because the hybrid-phonon frequencies are approximately equal to omega_L, the zone center LO-phonon frequency of the quantum well material. This is because there is not much hybridisation? (so they are mostly LO-phonon -like, and so the dispersion is small).

"these involve the precise definition of optical stress, as opposed to acoustic stress", "and the appearance of surface terms". This is relevant to the TO-phonon boundary-condition analogous to the LO-phonon pressure boundary-condition, I suspect -- although the acoustic-phonon stress term was on u_z. Is there a problem over optical pressure too? (whatever that might be). Note that Ridley-ACB-1994 use elastic stresses and optical strains in describing a free-standing optical slab.

XINDEX: log-file, hybrid-phonon, boundary-condition, Ridley-1993, Register-1992, LO-phonon, IP-phonon, DC-model, index-file, log-file.

19971127 1209 12 19980107

Email Feedback: Dr.Paul.Kinsler@physics.org