Dynamic nuclear polarisation in biased quantum wires with spin-orbit interaction

¹  Department of Theoretical Physics, Tata Institute of Fundamental Research - Homi Bhabha Road, Mumbai 400005, India
²  Theory of Condensed Matter Group, Cavendish Laboratory, Department of Physics, University of Cambridge J. J. Thomson Avenue, Cambridge CB3 0HE, UK

Received: 10 October 2007
Accepted: 21 January 2008

Abstract

We propose a new method for dynamic nuclear polarisation in a quasi–one-dimensional quantum wire utilising the spin-orbit interaction, the hyperfine interaction, and a finite source-drain potential difference. In contrast with current methods, our scheme does not rely on external magnetic or optical sources which makes independent control of closely placed devices much more feasible. Using this method, a significant polarisation of a few per cent is possible in currently available InAs wires which may be detected by conductance measurements. This may prove useful for nuclear-magnetic-resonance studies in nanoscale systems as well as in spin-based devices where external magnetic and optical sources will not be suitable.