Complex conductivity of $\rm Y_{1-x}Pr_xBa_2Cu_3O_7$ thin films measured by coherent terahertz spectroscopy

TL;DR

This study measures the complex terahertz conductivity of Y_{1-x}Pr_xBa_2Cu_3O_7 thin films, revealing temperature-dependent features related to superconductivity and possible spin gap phenomena.

Contribution

It introduces a method to determine complex conductivity without Kramers-Kronig analysis and reports new temperature-dependent conductivity behaviors in Pr-doped cuprate films.

Findings

Superconducting samples exhibit a peak in conductivity below T_c.

Underdoped samples deviate from expected behavior above T_c.

Possible link between conductivity deviations and spin gap onset.

Abstract

The complex transmission of Y_{1-x}Pr_xBa_2Cu_3O_7 single crystal thin films has been measured in the range 0.2-1.0 THz using time domain spectroscopy. The complex conductivity is calculated without using a Kramers-Kronig analysis. All of the superconducting samples show a peak in $\sigma_1(T)$ below $T_c$. The underdoped samples show a deviation from $1/(\alpha+\beta T)$ behavior above $T_c$ that may be linked with the onset of a spin gap.