Spontaneous spin polarization in quantum wires

Materials Science Division, Argonne National Laboratory - Argonne, IL 60439, USA

Received: 18 January 2006
Accepted: 23 March 2006

Abstract

A number of recent experiments report spin polarization in quantum wires in the absence of magnetic fields. These observations are in apparent contradiction with the Lieb-Mattis theorem, which forbids spontaneous spin polarization in one dimension. We show that sufficiently strong interactions between electrons induce deviations from the strictly one-dimensional geometry and indeed give rise to a ferromagnetic ground state in a certain range of electron densities.