Spatial Symmetry of Superconducting Gap in YBa2Cu3O7-\delta Obtained from Femtosecond Spectroscopy

TL;DR

This study uses polarized femtosecond spectroscopy on well-characterized YBa2Cu3O7- thin films to reveal the anisotropic nature of the superconducting gap, supporting the d-wave symmetry in cuprate superconductors.

Contribution

It demonstrates the effectiveness of polarized femtosecond spectroscopy combined with textured samples to probe the anisotropic superconducting gap in different crystal orientations.

Findings

Significant anisotropy in transient reflectivity and relaxation times.

Evidence supporting d-wave symmetry of the superconducting gap.

Orientation-dependent quasiparticle relaxation dynamics.

Abstract

The polarized femtosecond spectroscopies obtained from well characterized (100) and (110) YBa2Cu3O7-\delta thin films are reported. This bulk-sensitive spectroscopy, combining with the well-textured samples, serves as an effective probe to quasiparticle relaxation dynamics in different crystalline orientations. The significant anisotropy in both the magnitude of the photoinduced transient reflectivity change and the characteristic relaxation time indicates that the nature of the relaxation channel is intrinsically different in various axes and planes. By the orientation-dependent analysis, d-wave symmetry of the bulk-superconducting gap in cuprate superconductors emerges naturally.