Tunneling time for phonons: dependence on the system's size



We discuss the physical conditions under which the tunneling time for long-wavelength phonons through semiconductor heterostructures is independent of the system's size, i.e. the effect equivalent to the Hartman effect for electrons. An analysis of the vibrational energy stored in the system is shown to be relevant for this study. In fact, the phonon Hartman effect is explained on the basis of saturation of the stored vibrational energy. Both acoustic and optical phonons are considered. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)