Time reversal symmetry breaking in cuprates induced by the spiral spin order

TL;DR

This paper suggests that the observed time reversal symmetry breaking in cuprates' pseudogap state may originate from local spiral spin structures influenced by spin-orbit interaction, offering a new interpretation of experimental ARPES dichroism signals.

Contribution

It introduces a novel explanation linking TRSB in cuprates to local spiral spin order, differing from previous micro-current theories.

Findings

TRSB dichroism may be connected to spiral spin structures.

Angular dependence of dichroism supports the spiral spin hypothesis.

Proposes tests to distinguish spiral spin order from micro-current states.

Abstract

We propose a new interpretation of the spontaneous time reversal symmetry breaking (TRSB) observed recently in a pseudogap state of cuprate (Kaminsky et al.). It is shown that the TRSB dichroism in ARPES signal may be connected with the local spiral spin structures in system. It may be caused by a spin-orbit interaction and by spin polarization of electrons at various sections of Fermi surface in spiral state. Angular dependence of dichroism signal is studied in schematic KKR approximation. Tests are proposed to check an existence of the local spiral spin structure and to distiguish it from the TRSB state with micro-currents constructed by Varma.