Site symmetry approach to lattice dynamics of semiconductor superlattices

• Published in: Superlattices and microstructures 1991, Vol.9 (2), p.211-217
• Main Authors: Bairamov, B.H., Evarestov, R.A., Kitaev, Yu.E., Jahne, E., Delaney, M., Gant, T.A., Klein, M.V., Levi, D., Klem, J., Morkoc, H.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0749-6036; 1096-3677
• DOI: 10.1016/0749-6036(91)90284-X

We present here the site symmetry approach to lattice dynamics of superlattices which permits us to connect by symmetry the local atomic displacements and normal vibrational modes over the entire Brillouin zone. The atomic arrangements over the Wyckoff positions for (GaAs) m(AlAs) n and (Si) m(Ge) n superlattices oriented along [001] for different sets of m and n are determined. We obtained the phonon symmetry for k ≠ 0 using the developed theory of the band representations of space groups and derived the selection rules for the first and second-order infrared and Raman spectra. Raman spectra obtained for the (GaAs) 7(AlAs) 18 and (Si) 3(Ge) 3 superlattices are interpreted in terms of the presented theory.