Possible evidence of a spontaneous spin polarization in mesoscopic two-dimensional electron systems.
We have experimentally studied the nonequilibrium transport in low-density clean two-dimensional (2D) electron systems at mesoscopic length scales. At zero magnetic field (B), a double-peak structure in the nonlinear conductance was observed close to the Fermi energy in the localized regime. From the behavior of these peaks at nonzero B, we could associate them with the opposite spin states of the system, indicating a spontaneous spin polarization at B=0. Detailed temperature and disorder dependence of the structure shows that such a splitting is a ground-state property of low-density 2D systems.
Ghosh
A
A
Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, United Kingdom.
Ford
C J B
CJ
Pepper
M
M
Beere
H E
HE
Ritchie
D A
DA