Doping dependent time-reversal symmetric nonlinearity of YBa_2Cu_3O_7-d thin films

TL;DR

This study investigates how doping levels affect the time-reversal symmetric nonlinear response in YBa_2Cu_3O_7-d thin films, revealing increased nonlinearity with under-doping and linking it to the condensation energy.

Contribution

It provides the first detailed analysis of doping-dependent nonlinearity in YBa_2Cu_3O_7-d, connecting nonlinear response to intrinsic properties near Tc.

Findings

Nonlinearity increases as the sample becomes more under-doped.

Intrinsic Ginzburg-Landau nonlinearity is doping dependent.

Results align with the doping dependence of condensation energy.

Abstract

We have measured the temperature dependent third harmonic response from a series of under-doped YBa_2Cu_3O_7-d thin films to address the mechanism of nonlinearity in these samples. We find that the intrinsic Ginzburg-Landau nonlinearity near Tc is doping dependent, with the sample becoming more nonlinear as it is under-doped. The results are consistent with the doping dependence of the condensation energy of YBa_2Cu_3O_7-d.