12 research outputs found
Pressure dependence of two-level systems in disordered atomic chain
The dependence of two-level systems in disordered atomic chain on pressure,
both positive and negative was studied numerically. The disorder was produced
through the use of interatomic pair potentials having more than one energy
minimum. It was found that there exists a correlation between the energy
separation of the minima of two-level systems Delta and the variation of this
separation with pressure. The correlation may have either positive or negative
sign, implying that the asymmetry of two-level systems may in average increase
or decrease with pressure depending on the interplay of different interactions
between atoms in disordered state. The values of Delta depend on the sign of
pressure.Comment: 5 pages, 5 figure
Self-consistent theory of intrinsic localized modes: application to monatomic chain
A theory of intrinsic localized modes (ILMs) in anharmonic lattices is
developed, which allows one to reduce the original nonlinear problem to a
linear problem of small variations of the mode. This enables us to apply the
Lifshitz method of the perturbed phonon dynamics for the calculations of ILMs.
In order to check the theory, the ILMs in monatomic chain are considered. A
comparison of the results with the corresponding molecular dynamics
calculations shows an excellent agreement.Comment: 9 pages, 1 figure, 1 tabl