Colloquium on May 5, 2009

Yuriy A. Kosevich
Semenov Institute of Chemical Physics, Russian Academy of Sciences Moscow

Bloch acceleration theorem and Bloch oscillations in complex electronic, acoustic and magnetic systems

Bloch oscillations and Landau-Zener tunneling are the fundamental properties of quantum dynamics of a particle in a periodic potential subject to an external static force. The wave-particle dualism leads to completely counterintuitive behaviour of Bloch-oscillating wavepacket-particle, which attracted for years substantial interest in its deep theoretical understanding and clear experimental observation.

In this talk we will discuss several aspects of semiclassical approach, based on Bloch acceleration theorem, which allows one to understand and describe Bloch oscillations in systems of very different nature, including complex electronic, acoustic and magnetic systems. We will show the usefulness of such approach for quantitative description of the available experimental data on Bloch oscillations of coherent electronic wavepackets, optically produced under different excitation conditions in semiconductor superlattices subjected to static electric and magnetic fields with different mutual orientation, and on Bloch oscillations of acoustic wavepackets in supersonic superlattices. Such approach is also useful for semiclassical modeling of Bloch oscillations of magnons and spin complexes in quasi-one-dimensional magnetic systems.