"Phason Dynamics in Aperiodic Crystals"
Prof. Ted Janssen
Institute for Theoretical
Physics, University of Nijmegen, The Netherlands
Crystals without periodicity are commonly found, but they are less known
than periodic crystals. They share many properties with each other, but
the behaviour of electrons and phonons in aperiodic crystals has a richer
In particular, there is a typical dynamic behaviour associated to the fact
that these materials may be seen as periodic structures in a higher-dimensional
space. The additional dimensions make it possible to find extra hydrodynamic
modes under certain conditions. These modes have a low frequency.
The question will be discussed whether these low frequency modes remain
when the amplitudes become large.
Under certain conditions, to be discussed here, low frequency or low
friction modes are still present. These waves are a type of solitary waves.
Their properties will be discussed for a number of classes of aperiodic crystals.
It makes it possible to obtain unlubricated almost frictionless motion.
Dr. Ron Lifshitz, x5145