A calculation for polar Kerr effect in high temperature cuprate superconductors

TL;DR

This paper proposes a phenomenological mechanism explaining the polar Kerr effect in high-temperature cuprate superconductors without breaking global time reversal symmetry, involving intra-bilayer tunneling and chiral d-density waves.

Contribution

It introduces a new explanation for the Kerr effect in cuprates that does not require global time reversal symmetry breaking, focusing on intra-bilayer tunneling and chiral order.

Findings

Kerr angle signs are identical from opposite faces of the sample.

The mechanism results in zero Faraday effect.

It applies to bilayer cuprates like YBCO with chiral d-density waves.

Abstract

A mechanism is proposed for the tantalizing evidence of polar Kerr effect in a class of high temperature superconductors--the signs of the Kerr angle from two opposite faces of the same sample are identical and magnetic field training is non-existent. The mechanism does not break global time reversal symmetry, as in an antiferromagnet, and results in zero Faraday effect. It is best understood in a phenomenological model of bilayer cuprates, such as YBCO, in which intra-bilayer tunneling nucleates a chiral d-density wave such that the individual layers have opposite chirality. Although specific to the chiral d-density wave, the mechanism may be more general to any quasi-two-dimensional orbital antiferromagnet in which time reversal symmetry is broken in each plane, but not when averaged macroscopically.