Pseudogap Phase Boundary in Overdoped Bi_2Sr_2CaCu_2O_8 Studied by Measuring Out-of-plane Resistivity under the Magnetic Fields

TL;DR

This study investigates the pseudogap phase boundary in overdoped Bi2Sr2CaCu2O8 by measuring out-of-plane resistivity under magnetic fields, revealing that pseudogap and superconductivity are distinct phenomena.

Contribution

It provides systematic evaluation of the pseudogap temperature in overdoped Bi2Sr2CaCu2O8 using resistivity measurements under magnetic fields, highlighting differences from superconductivity.

Findings

Pseudogap temperature T* decreases with doping.

Pseudogap and superconductivity are separate phenomena.

Magnetic fields induce upturn behavior in resistivity.

Abstract

The characteristic pseudogap temperature T* in Bi2Sr2CaCu2O8 system has been systematically evaluated as a function of doping, especially focusing on its overdoped region, by measuring the out-of-plane resistivity under the magnetic fields. Overdoped samples have been prepared by annealing TSFZ-grown Bi2Sr2CaCu2O8 single crystals under the high oxygen pressures (990 kgf/cm2). At a zero field, the out-of-plane resistivity showed a metallic behavior down to Tc (= 62 K), while under the magnetic fields of over 3 T,it showed typical upturn behavior from around 65 K upon decreasing temperature. This result suggests that the pseudogap and superconductivity are different phenomena.