Effect of magnetic field on competition between superconductivity and charge order below the pseudogap state

TL;DR

This paper models the phase diagram of cuprates under magnetic fields, revealing a temperature-independent transition to a charge order phase at low temperatures and a sharp increase in critical field at higher temperatures, aligning with experimental data.

Contribution

It introduces a theoretical SU(2) non-linear sigma-model to describe the competition between superconductivity and charge order in cuprates under magnetic fields, providing new insights into the phase diagram.

Findings

Critical magnetic field B_{QDW} is nearly temperature-independent at low T.

B_{QDW}(T) sharply increases beyond T_c.

Model results agree with sound velocity measurements.

Abstract

We theoretically investigate the T-B phase diagram of cuprates building on the SU(2) pseudogap order recently obtained from the spin-fermion model. At low temperatures, our analysis reveals an almost temperature-independent critical magnetic field B_{QDW} at which d-wave superconductivity switches to the quadrupole density wave (QDW) phase. For temperatures beyond a certain value of the order of the zero-field superconducting transition temperature T_c, the critical field B_{QDW}(T) sharply grows. We compare our results derived within the effective SU(2) non-linear sigma-model with the phase diagram recently obtained by sound velocity measurements by LeBoeuf et al. [Nat. Phys. 9, 79 (2013)].