Critical microwave-conductivity fluctuations across the phase diagram of superconducting La$_{2-x}$Sr$_x$CuO$_4$ thin films

Haruhisa Kitano; Takeyoshi Ohashi; Atsutaka Maeda; Ichiro Tsukada

doi:10.1103/PhysRevB.73.092504

paper

Critical microwave-conductivity fluctuations across the phase diagram of superconducting La $_{2 - x}$ Sr $_{x}$ CuO $_{4}$ thin films

arXiv:cond-mat/0601243 · doi:10.1103/PhysRevB.73.092504

Abstract

We report a systematic study of the dynamic microwave conductivity near $T_{c}$ for La $_{2 - x}$ Sr $_{x}$ CuO $_{4}$ (LSCO) thin films with $x$ =0.07 to 0.16. The strong frequency dependence of the phase stiffness together with scaling analysis of the ac fluctuating conductivity of superconductivity provide direct evidence for the 2D-XY behavior of nearly decoupled CuO $_{2}$ planes in underdoped LSCO ( $x$ =0.07 and 0.12). On the other hand, the critical exponents for slightly overdoped LSCO ( $x$ =0.16) were found to agree with those for the relaxational 3D-XY model, indicating that the universality class in LSCO is changed by hole doping. The implication of these results for the phase diagram of high- $T_{c}$ cuprates is discussed.

4pages, 4 figures

Critical microwave-conductivity fluctuations across the phase diagram of superconducting La2−x​Srx​CuO4​ thin films

Abstract

Critical microwave-conductivity fluctuations across the phase diagram of superconducting La $_{2 - x}$ Sr $_{x}$ CuO $_{4}$ thin films