Effect of LaAlO3 twin-domain topology on local dc and microwave properties of cuprate films

TL;DR

This study uses low temperature laser scanning microscopy to map local optical, superconducting, and microwave nonlinear properties of YBCO/LAO microstrip resonators, revealing how twin-domain topology influences local nonlinear and electronic transport behaviors.

Contribution

It provides detailed spatial correlation between microwave nonlinearity and dc transport properties, highlighting the impact of twin-domain topology on superconducting film behavior.

Findings

Direct spatial correlation between nonlinear microwave and dc transport properties.

Local nonlinear current densities match local critical current densities.

Twin-domain topology significantly influences local superconducting properties.

Abstract

Different imaging modes of low temperature laser scanning microscopy (LTLSM) have been applied to probe local optical and superconducting properties, as well as the spatial variations in thermoelectric and electronic (both dc and rf) transport, in a YBa_2Cu_3O_6.95 /LaAlO_3 (YBCO/LAO) superconducting microstrip resonator with micron-range resolution. Additionally, the local sources of microwave nonlinearity (NL) were mapped in two-dimensions simultaneously by using the LTLSM in two-tone rf intermodulation distortion contrast mode as a function of (x,y) position of the laser beam perturbation on the sample. The influence of the direction of individual twin-domain YBCO blocks on its NL properties was analyzed in detail. The result shows the direct spatial correlation between NL microwave and dc electronic transport properties of the YBCO film that are imposed by the underlying twin-domain topology of the LAO substrate. In these circumstances, the scale of local NL current densities J_IM(x,y) in different areas of the YBCO microstrip quantitatively coincide with the scale of local critical current densities J_c(x,y) measured at the same positions.