Two mechanisms of pseudogap formation in Bi-2201: Evidence from the c-axis magnetoresistance
Central Research Institute of Electric Power Industry
2-11-1 Iwato-kita, Komae, Tokyo 201-8511, Japan
Accepted: 26 October 2001
Measurements of the c-axis resistivity and magnetoresistance have been used to investigate the pseudogap (PG) behavior in BiSrLaxCuOy (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