Shot-noise signatures of 0.7 structure and spin in a quantum point contact

Phys Rev Lett. 2006 Jul 21;97(3):036810. doi: 10.1103/PhysRevLett.97.036810. Epub 2006 Jul 21.

Abstract

We report simultaneous measurement of shot noise and dc transport in a quantum point contact as a function of source-drain bias, gate voltage, and in-plane magnetic field. Shot noise at zero field exhibits an asymmetry related to the 0.7 structure in conductance. The asymmetry in noise evolves smoothly into the symmetric signature of spin-resolved electron transmission at high field. Comparison to a phenomenological model with density-dependent level splitting yields good quantitative agreement.