Coherent confined LO phonons in 70Ge/74Ge isotope superlattices generated by ultrafast laser pulses

M. Nakajima, H. Harima, K. Morita, Kohei M Itoh, K. Mizoguchi, E. E. Haller

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Generation of high-order coherent confined LO phonon modes by 20-fs ultrashort laser pulse irradiation was observed in a new class of nonpolar semiconductors; 70Ge/74Ge isotope superlattices. The phonon oscillations were Fourier transformed and compared with a theoretical calculation based on a planar force-constant model and a bond polarizability approach. The comparison between the calculated and Fourier transformed spectra shows clearly that the amplitudes of coherent phonons are determined solely by the degree of the atomic displacement and that only the Raman active odd-number-order modes are observable. The spectra taken with variety of polarization of pump beam show clearly that the generation mechanism of coherent phonons in nonpolar semiconductor like Ge is stimulated Raman scattering.

Original languageEnglish
Article number161304
Pages (from-to)1613041-1613044
Number of pages4
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume63
Issue number16
Publication statusPublished - 2001

Fingerprint

Ultrafast lasers
Superlattices
Phonons
Isotopes
superlattices
Laser pulses
phonons
isotopes
Semiconductor materials
Stimulated Raman scattering
Laser modes
pulses
Ultrashort pulses
lasers
Irradiation
Pumps
Polarization
Raman spectra
pumps
oscillations

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Nakajima, M., Harima, H., Morita, K., Itoh, K. M., Mizoguchi, K., & Haller, E. E. (2001). Coherent confined LO phonons in 70Ge/74Ge isotope superlattices generated by ultrafast laser pulses. Physical Review B - Condensed Matter and Materials Physics, 63(16), 1613041-1613044. [161304].

Coherent confined LO phonons in 70Ge/74Ge isotope superlattices generated by ultrafast laser pulses. / Nakajima, M.; Harima, H.; Morita, K.; Itoh, Kohei M; Mizoguchi, K.; Haller, E. E.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 63, No. 16, 161304, 2001, p. 1613041-1613044.

Research output: Contribution to journalArticle

Nakajima, M, Harima, H, Morita, K, Itoh, KM, Mizoguchi, K & Haller, EE 2001, 'Coherent confined LO phonons in 70Ge/74Ge isotope superlattices generated by ultrafast laser pulses', Physical Review B - Condensed Matter and Materials Physics, vol. 63, no. 16, 161304, pp. 1613041-1613044.
Nakajima, M. ; Harima, H. ; Morita, K. ; Itoh, Kohei M ; Mizoguchi, K. ; Haller, E. E. / Coherent confined LO phonons in 70Ge/74Ge isotope superlattices generated by ultrafast laser pulses. In: Physical Review B - Condensed Matter and Materials Physics. 2001 ; Vol. 63, No. 16. pp. 1613041-1613044.
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