Bond order in two-dimensional metals with antiferromagnetic exchange interactions

Understand

We present an unrestricted Hartree-Fock computation of charge-ordering instabilities of two-dimensional metals with antiferromagnetic exchange interactions, allowing for arbitrary ordering wavevectors and internal wavefunctions of the particle-hole pair condensate.

• We find that the ordering has a dominant d symmetry of rotations about lattice points for a range of ordering wavevectors, including those observed in recent experiments at low temperatures on YBCO.
• This d symmetry implies the charge ordering is primarily on the bonds of the Cu lattice, and we propose incommensurate bond order parameters for the underdoped cuprates.
• The field theory for the onset of Neel order in a metal has an emergent pseudospin symmetry which `rotates' d-wave Cooper pairs to particle-hole pairs (Metlitski et al.