Diode Effect May Assist Finding Proper Superconductivity Mechanism in Copper Oxides

TL;DR

This study demonstrates zero-field superconducting diode effects in copper-oxide high-temperature superconductors, suggesting intrinsic time-reversal symmetry breaking, which constrains theoretical models of their superconducting mechanisms.

Contribution

It provides experimental evidence of intrinsic time-reversal symmetry breaking in cuprates through zero-field diode effects, advancing understanding of their superconducting state.

Findings

Superconducting diode effect observed at 100 K without external magnetic fields.

The diode effect persists under magnetic fields up to ±100 Oe.

Results support the idea that time-reversal symmetry breaking is intrinsic to cuprate superconductors.

Abstract

We present measurements demonstrating that copper-oxide high-temperature superconductors can exhibit broken time-reversal symmetry in the absence of external magnetic fields. Using $Tl_{2}Ba_{2}CaCu_{2}O_{8}$ microbridges, we observe a pronounced superconducting diode effect at 100 K under strictly zero-field conditions. This nonreciprocal response remains unchanged in magnetic fields up to $\pm 100 Oe$. Our results are consistent with recent reports of zero-field diode behavior in $Bi_{2}Sr_{2}CaCu_{2}O_{8+{\delta} }$ and together indicate that time-reversal symmetry breaking may be an intrinsic property of the cuprate superconducting state. These findings significantly constrain theoretical models of high-temperature superconductivity that rely on time-reversal-symmetric mechanisms.