Spontaneous spin polarization in quantum point contacts

Phys Rev Lett. 2006 Apr 21;96(15):156602. doi: 10.1103/PhysRevLett.96.156602. Epub 2006 Apr 21.

Abstract

We use spatial spin separation by a magnetic focusing technique to probe the polarization of quantum point contacts. The point contacts are fabricated from p-type GaAs/AlGaAs heterostructures. A finite polarization is measured in the low-density regime, when the conductance of a point contact is tuned to < 2e2/h. Polarization is stronger in samples with a well-defined "0.7 structure."