Pseudogap and Conduction Dimensionalities in High-T_c Superconductors

TL;DR

This paper investigates the transition of conduction and gap dimensionalities in high-T_c superconductors YBa2Cu3O7−δ and Bi2Sr2Ca1−xYxCu2O8 by analyzing resistivity curves with advanced models, revealing a 2D to 3D transition influenced by oxygen and calcium content.

Contribution

It introduces a combined resistivity modeling approach using Fermi liquid and ionization energy models coupled with charge-spin separation to analyze conduction dimensionalities in high-T_c superconductors.

Findings

Resistivity curves indicate a 2D to 3D conduction transition with oxygen and calcium reduction.

The c-axis pseudogap may be distinct from the superconducting and spin gaps.

MgB2 superconductor differs from Y123 and Bi2212 types based on the models.

Abstract

The nature of normal state charge-carriers' dynamics and the transition in conduction and gap dimensionalities between 2D and 3D for YBa_2 Cu_3 O_{7-delta} and Bi_2 Sr_2 Ca_{1-x} Y_x Cu_2 O_8 high-T_c superconductors were described by computing and fitting the resistivity curves, rho(T,delta,x). These were carried out by utilizing the 2D and 3D Fermi liquid (FL) and ionization energy (E_I) based resistivity models coupled with charge-spin (CS) separation based t-J model [Phys. Rev. B 64, 104516 (2001)]. rho(T,delta,x) curves of Y123 and Bi2212 samples indicate the beginning of the transition of conduction and gap from 2D to 3D with reduction in oxygen content (7-delta) and Ca^{2+} (1-x) as such, c-axis pseudogap could be a different phenomenon from superconductor and spin gaps. These models also indicate that the recent MgB_2 superconductor is at least not Y123 or Bi2212 type.