We consider tunnelling between a metal partially gapped by charge density waves (CDWM) and an
ordinary metal (M) or a ferromagnet (FM) separated by an insulator (I) in an external magnetic field
H. Zeeman paramagnetic splitting is assumed to dominate in the
CDWM over orbital magnetic effects. The quasiparticle tunnel current
J and relevant
differential conductance G
are calculated as functions of the bias voltage
V. The
peaks of G(V), originating from the electron density of states singularities near the charge
density wave gap edges, were shown to be split in the magnetic field, each
peak having a predominant spin polarization. This effect is analogous to the
H-induced
splitting of G(V)
peaks obtained by Tedrow and Meservey for junctions between normal metals
and superconductors (S). Thus, it is possible to electrically measure the
polarization of current carriers in such a set-up, although the behaviours of
G(V)
in the two cases are substantially different. The use of M–I–CDWM junctions instead of
M–I–S ones has certain advantages. The absence of the Meissner effect, which weakens
the constraints upon the junction geometry and electrode materials, comprises
the main benefit. The other advantage is the larger energy range of the charge
density wave gaps in comparison to that for superconductors’ gaps, so that larger
Hs
may be applied.