Eur. Phys. J. B 40, 445-452 (2004)
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

Abstract

In high temperature (high T_c) cuprate superconductors the gap in the electronic density of states is not fully filled at T_c; it evolves into a partial (pseudo)gap that survives way beyond T_c, 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 H_pg. We found that H_pg 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 H_pg 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.