https://doi.org/10.1140/epjb/e2004-00348-9
What are spin currents in Heisenberg magnets?
1
Institut für Theoretische Physik, Universität
Frankfurt, Robert-Mayer-Strasse 8, 60054 Frankfurt, Germany
2
Theoretische Physik III, Elektronische Korrelationen und
Magnetismus, Institut für Physik, Universität Augsburg,
86135 Augsburg, Germany
Corresponding author: a schuetz@itp.uni-frankfurt.de
Received:
27
May
2004
Revised:
1
September
2004
Published online:
5
November
2004
We discuss the proper definition of the spin current operator in
Heisenberg magnets subject to inhomogeneous magnetic fields. We
argue that only the component of the naive “current operator”
in the plane spanned by the local
order parameters 
and 
is related to real transport of magnetization.
Within a mean field approximation or in the classical ground state
the spin current therefore vanishes. Thus, finite spin currents are
a direct manifestation of quantum correlations in the system.
PACS: 75.10.Jm – Quantized spin models / 75.10.Pq – Spin chain models / 75.30.Ds – Spin waves / 73.23.Ra – Persistent currents
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2004
