Effects of the mixture of one- and three-dimensional inhomogeneities on the wave spectrum of superlattices
V. A. Ignatchenko, Yu. I. Mankov, A. A. Maradudin*
L. V. Kirensky Institute of Physics, 660036 Krasnoyarsk, Russia
*Department of Physics and Astronomy University of California, Irvine CA 92697, USA
PACS: 68.65.-k, 75.30.Ds
Abstract
Dependences of the dispersion laws and damping of waves in an
initially sinusoidal superlattice on the dimensionality of
inhomogeneities modulating the period of the superlattice are
studied. The cases of one- and three- dimensional modulations, as
well as modulation by a mixture of inhomogeneities of both of
these dimensionalities, are considered. The correlation function of
the superlattice K( r) has the form of a product of the same
periodic function and a decreasing function that is significantly
different for these different cases. The
decreasing part of the correlation function for the mixture of
inhomogeneities of different dimensionalities has the form of a
product of the decreasing parts of the correlation functions of
the components of the mixture. This leads to the non-additivity of
the contributions of the components of different dimensionalities
to the resulting modification of the parameters of the wave
spectrum that are due to the inhomogeneities (the damping of
waves for the mixture of these components is smaller than the sum of
the dampings of the components, the maximum gap in the spectrum
corresponds to the simultaneous presence of both components of
the mixture, not only of the three-dimensional inhomogeneities).