1203.5776 (Gia-Wei Chern et al.)

Broken translational symmetry in an emergent paramagnetic phase of
graphene    [PDF]

Gia-Wei Chern, Rafael M. Fernandes, Rahul Nandkishore, Andrey V. Chubukov

We show that the spin-density wave state near the 3/8 or 5/8-filling of the honeycomb lattice 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 STM. We also show that spin fluctuations are also enhanced in this emergent phase, leaving distinctive signatures in the magnetic spectrum that can be probed experimentally.

View original: http://arxiv.org/abs/1203.5776