Technion-Israel Institute of Technology Departement of Physics, Haifa, Israel
Technische Universität Berlin Fachbereich Mathematik MA 7 - 2 Strasse des 17. Juni 136 D-1000, Berlin, Germany
Abstract:
We consider a particle in a 2 dimensional plane in a periodic potential and a homogeneous magnetic field perpendicular to the plane. Kubo's expression for conductivity of the Hall current is an integer.
This result of Thouless, Kohomoto, Nightingale and den Nijs is interpreted geometrically.