DOI: 10.1209/epl/i2002-00571-0


Europhys. Lett., 57 (2) , p. 267 (2002)

Two mechanisms of pseudogap formation in Bi-2201: Evidence from the c-axis magnetoresistance

A. N. Lavrov, Y. Ando and S. Ono

Central Research Institute of Electric Power Industry 2-11-1 Iwato-kita, Komae, Tokyo 201-8511, Japan

(Received 14 June 2001; accepted in final form 26 October 2001)

Abstract
Measurements of the c-axis resistivity and magnetoresistance have been used to investigate the pseudogap (PG) behavior in Bi _2+zSr _2-x-zLa _xCuO _y (Bi-2201) crystals at various hole densities. While the PG opening temperature T^* increases with decreasing hole doping, the magnetic-field sensitivity of the PG is found to have a very different trend: it appears at lower temperatures in more underdoped samples and vanishes in non-superconducting samples. These data suggest that besides the field-insensitive pseudogap emerging at T^*, a distinct one is formed above as a precursor to superconductivity.

PACS
74.25.Fy - Transport properties (electronic and thermal conductivity).
74.20.Mn - Non-conventional mechanisms (spin fluctuations, polarons and bipolarons, resonating valence bond model, anyon mechanism, marginal Fermi liquid, Luttinger liquid, etc.).
74.72.Hs - Bi-based cuprates.


© EDP Sciences 2002