Broken translational symmetry in an emergent paramagnetic phase of graphene

TL;DR

This paper reveals a novel paramagnetic phase in graphene that breaks translational symmetry while preserving rotational symmetry, characterized by a Z_4 symmetry breaking and detectable via STM and magnetic spectrum analysis.

Contribution

It introduces a new emergent paramagnetic phase in graphene that breaks translational symmetry without affecting rotational symmetry, differing from known phases.

Findings

The phase breaks an emergent Z_4 symmetry.

It preserves lattice rotational symmetry.

It creates a detectable super-lattice structure.

Abstract

We show that the spin-density wave state on the partially filled honeycomb and triangular lattices is preempted by a paramagnetic phase that breaks an emergent Z_4 symmetry of the system, associated with the four inequivalent arrangements of spins in the quadrupled unit cell. Unlike other emergent paramagnetic phases in itinerant and localized-spin systems, this state preserves the rotational symmetry of the lattice but breaks its translational symmetry, giving rise to a super-lattice structure that can be detected by scanning tunneling microscopy. This emergent phase also has distinctive signatures in the magnetic spectrum that can be probed experimentally.