No evidence for spontaneous orbital currents in finite size studies of three-band models for CuO planes

TL;DR

This study uses numerical methods to investigate three-band models of CuO planes in high-T_c superconductors, finding no evidence for proposed orbital current patterns and suggesting such patterns are unlikely to explain high-energy phenomena.

Contribution

The paper provides the first numerical evaluation of current-current correlations in three-band models, challenging the existence of proposed orbital current patterns in CuO planes.

Findings

No evidence for orbital current patterns at hole doping x=1/8

Estimated energy of potential patterns is less than 5 meV per link

Orbital current fluctuations are unlikely to cause high-energy phenomena like superconductivity

Abstract

We have numerically evaluated the current-current correlations for three-band models of the CuO planes in high-T_c superconductors at hole doping x=1/8. The results show no evidence for the orbital current patterns proposed by Varma. If such patterns exist, the associated energy is estimated to be smaller than 5 meV per link even if epsilon_p-epsilon_d=0. Assuming that the three-band models are adequate, quantum critical fluctuations of such patterns hence cannot be responsible for phenomena occurring at significantly higher energies, such as superconductivity or the anomalous properties of the pseudogap phase.