Coherent terahertz acoustic vibrations in polar and semipolar gallium nitride-based superlattices

Moss, D M and Akimov, A V and Kent, A J and Glavin, B A and Kappers, M J and Hollander, J L and Moram, M A and Humphreys, C J


The femtosecond optical pump-probe technique is used to generate and detect the coherent acoustic vibrations with a frequency 0.83×1012Hz in polar (0001) and semipolar (11-22) InGaN/GaNsuperlattices. The measured amplitude of the vibrations in the semipolar sample is about five times smaller that in the polar one. Analysis of the experimental data and theoretical estimates suggest that, in addition to piezoelectric, deformation potential provides essential contribution to both generation and detection of vibrations, especially in the semipolar superlattice.

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Department of Materials
Imperial College London
Royal School of Mines
Exhibition Road
London, SW7 2AZ - UK