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Zeitschrift für Physik B Condensed Matter
ISSN: 0722-3277 (printed version)
ISSN: 1431-584X (electronic version)
Abstract Volume 100 Issue 3 (1996) pp 353-364
Interaction between an electron and optical phonons in polar semiconductor heterostructures
Jun-Jie Shi (1)(2), Shao-Hua Pan (1)(3), Zi-Xin Liu (2)
(1) CCAST (World Laboratory), P.O. Box 8730, Beijing 100080, People's Republic of China
(2) Department of Physics, Henan Normal University, Henan, Xinxiang 453002, People's Republic of China
(3) Institute of Physics, Chinese Academy of Sciences, P.O.Box 603, Beijing 100080, People's Republic of China (Fax: 86-1-2562605, e-mail: user308@aphy01.iphy.ac.cn)
Received: 8 June 1995/Revised version: 1 September 1995
Abstract. Interface phonons and bulk-like longitudinal-optical (LO) phonons and their interaction with an electron are studied for a finite four-layer heterostructure (FFLHS). An analysis of the field eigenvectors shows that, in the vicinity of the Brillouin-zone center, an interface transverse-optical (TO) mode oscillates at the bulk LO frequency, and an interface LO mode oscillates at the bulk TO frequency. Analytic expressions and numerical illustrations for dispersion relations of interface modes and for electron-phonon coupling functions and scattering rates are obtained for finite, semi-infinite and infinite quantum well (QW) structures which are important special cases of an FFLHS. It is shown that the scattering rates depend strongly on the well width of a QW structure, and that interface modes are much more important than bulk LO modes when the well width is small. The calculated results also show that the usual selection rules for intersubband and intrasubband transitions break down in asymmetric heterostructures. Moreover, we have found an interesting result. That is, in comparison with the negligibly small interaction between an electron and the lowest-frequency interface-mode in symmetric single QWs and commonly used step QWs, this interaction may be very large in asymmetric single QWs and general step QWs.
PACS: 63.20.Dj; 63.20.Kr; 72.10.Di
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