Lecturer

Alexander Chaplik

Title

NONEQUILIBRIUM  CHARGE  SPREADING  IN  2D  ELECTRONIC SYSTEMS

Date and Place

15:00 on July 7 (Wed), 2004 at room 827 of building 16, Komaba campus

Abstract

he relaxation in space and time of nonequlibrium charges injected in a 2D system is considered.

Principal different role of the Maxwell mechanism of relaxation in 2D as compared with 3D is demonstrated.

The spreading of a "spot" of the injected charge in a specimen of high mobility cannot be described by

electrostatic approximation and retardation effects (vertex fields) should be taken into account. The

relaxation in finite specimen in a perpendicular magnetic field looks like decaying oscillations and

the characteristic frequencies can be very slow on the quantum Hall plateaus. In the regime of the ideal

quantum Hall effect ( SIGMAxx = 0 ) the spreading occurs only due to vertex fields and the share of the

"gone-away" charge is quantized ( together with SIGMAxy).  Recently an experiment by Kotthaus

group  ( Munich) has been published with first observation of some of  predicted effects.