Hamburg 2001 – scientific programme

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DS: Dünne Schichten

DS 21: Schichteigenschaften IV

DS 21.3: Talk

Thursday, March 29, 2001, 10:00–10:15, S 13/14

Acoustoelastic anomaly in stressed heterostructures — •E. Chilla, A.V. Osetrov, and R. Koch — Paul Drude Institute for Solid State Electronics, Nanoacoustics group, Hausvogteiplatz 5-7, 10117 Berlin, Germany

We investigated the influence of stress on the acoustic wave propagation in single crystalline heterostructures using a transfer matrix method. Both Rayleigh-type and Sezawa modes exhibit an acoustoelastic anomaly, where the stress induced change of the phase velocity is maximum for finite film thicknesses, considerably smaller than the acoustic wavelength. For Ge/Si(001) compressed by 1 GPa the velocity shift of Sezawa modes reaches exceptionally high values of about 2 percent. These results demonstrate the importance of stress effects on the determination of elastic constants of thin film heterostructures.