PROBING OF LEVEL CORRELATION-EFFECTS IN QUANTUM DOTS BY SURFACE ACOUSTIC-WAVES

The attenuation, Gamma, of surface acoustic waves (SAWs) by an array o f isolated quantum dots is studied. The limiting cases of continuous a nd discrete energy spectra of the dots are discussed. The spectra are continuous when the SAW frequency omega is larger than the mean level spacing Delta or when the levels overlap due to broadening, tau(phi)(- 1) > Delta Lambda tau(phi)(-1) being the phase breaking rate. Discrete spectra are obtained for omega, tau(phi)(-1) < Delta. The sensitivity of Gamma with respect to the global symmetries (''weak localization e ffects'') is much more pronounced in the discrete spectrum limit, sinc e level correlation effects are resolved. The measurement of Gamma yie lds the temperature dependence of both tau(phi)(-1) and the equilibrat ion rate tau(phi)(-1) (C) 1998 Elsevier Science B.V. All rights reserv ed.