title: Weak plaquette valence bond order in the S = 1/2 honeycomb J1 - J2 Heisenberg model.
abstract: Using the density matrix renormalization group, we investigate the S = 1/2 Heisenberg model on the honeycomb lattice with first (J(1)) and second (J(2)) neighbor interactions. We are able to study long open cylinders with widths up to 12 lattice spacings. For J(2)/J(1) near 0.3, we find an apparently paramagnetic phase, bordered by an antiferromagnetic phase for J(2) ≲ 0.26 and by a valence bond crystal for J(2) ≳ 0.36. The longest correlation length that we find in this intermediate phase is for plaquette valence bond order. This correlation length grows strongly with cylinder circumference, indicating either quantum criticality or weak plaquette valence bond order.
authors.affiliation: Department of Physics and Astronomy, University of California, Irvine, California 92697, USA.
authors.forename: Zhenyue
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Huse
authors.affiliation: Department of Physics and Astronomy, University of California, Irvine, California 92697, USA.
authors.forename: Steven R
authors.initials: SR
authors.lastname: White