Anisotropic Optical Conductivity of Nd2-xCexCuO4 Thin Films

TL;DR

This study measures the anisotropic optical conductivity of Nd2-xCexCuO4 thin films using the R-T method, revealing d-wave pairing symmetry and gap nodes in electron-doped high-Tc superconductors through infrared spectroscopy.

Contribution

It provides the first detailed infrared optical conductivity analysis of Nd2-xCexCuO4 thin films, confirming d-wave pairing symmetry and gap nodes.

Findings

Optical conductivity spectra are consistent with d-wave pairing.

The R-T method effectively probes the superconducting gap.

Results support the presence of nodes in the superconducting gap.

Abstract

Opticcal conductivity spectra $\sigma_1(\omega)$ of Nd2-xCexCuO4 thin films, measured by the reflectance-transmittance method (R-T method) which has been proposed to investigate far-infrared spectroscopy, are investigated based on the anisotropic pairing model. Precise measurements of the frequency-dependent conductivity enable us to examine quantitatively the nature of the superconducting gap through infrared properties in the electron-doped high-Tc superconductors. We show that the behavior of optical conductivity $\sigma_1$ is consistent with the anisotropic superconducting gap and is well explained by the formula for d-wave pairing in the low-energy regime of the far-infrared region. Our results suggest that the electron-doped cuprate superconductors Nd2-xCexCuO4 have nodes in the superconducting gap.