Loop currents in ladder cuprates: A dynamical mean field theory study

TL;DR

This study uses cluster dynamical mean field theory to investigate the potential for spontaneous loop currents in ladder cuprates, finding no evidence of such currents without external influence.

Contribution

The paper applies CDMFT to a seven-band Hubbard model of ladder cuprates to explore spontaneous loop currents, a novel approach in this context.

Findings

No spontaneous loop currents observed without external field

Loop currents only induced by external field

Results suggest intrinsic stability against loop currents

Abstract

We investigate the possibility of spontaneous loop currents in the two-leg ladder cuprate Sr$_{14-x}$Ca$_x$Cu$_{24}$O$_{41}$ by applying cluster dynamical mean field theory (CDMFT) to a seven-band Hubbard model for that compound, with an exact diagonalization solver. We sample several values of the local interaction $U_d$ and of the Cu-O energy difference $E_{pd}$, by applying an external field that induces loop currents. We find no instance of spontaneous loop currents once the external field is brought to zero.