https://doi.org/10.1140/epjb/e2004-00248-0
High-field interlayer tunnelling transport in layered cuprates: Uncovering the pseudogap state
1
IBM T.J. Watson Research Center, Yorktown Heights, New
York 10598, USA
2
Department of Electronic Science and
Engineering, Kyoto University, Kyoto 615-8510, Japan
Corresponding author: a krusin@us.ibm.com
Received:
2
February
2004
Published online:
10
August
2004
In high temperature (high Tc) cuprate
superconductors the gap in the electronic density of states is not
fully filled at Tc; it evolves into a partial (pseudo)gap that
survives way beyond Tc, challenging the conventional views. We
have investigated the pseudogap phenomenon in the
field-temperature (
) diagram of Bi2Sr2CaCu2O
over a wide range of hole doping (
). Using
interlayer tunneling transport in magnetic fields up to 60 T to
probe the density-of states (DOS) depletion at low excitation
energies we mapped the pseudogap closing field Hpg. We found
that Hpg and the pseudogap onset temperature 
are
related via a Zeeman relation 
,
irrespective of whether the magnetic field is applied along the
c-axis or parallel to CuO2 planes. In contrast to large
anisotropy of the superconducting state, the field anisotropy of
Hpg is due solely to the g-factor. Our findings indicate
that the pseudogap is of singlet-spin origin, consistent with
models based on doped Mott insulator.
PACS: 74.25.Dw – Superconductivity phase diagrams / 74.25.Fy – Transport properties (electric and thermal conductivity, thermoelectric effects, etc.) / 74.72.Hs – Bi-based cuprates
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2004
