Deconfined criticality in the frustrated Heisenberg honeycomb antiferromagnet

TL;DR

This study maps the phase diagram of a frustrated spin-1/2 Heisenberg antiferromagnet on a honeycomb lattice, revealing continuous phase transitions indicative of deconfined quantum criticality.

Contribution

It provides the first detailed numerical evidence of deconfined criticality in a honeycomb lattice antiferromagnet with frustration.

Findings

Identified Neel, plaquette, and dimer phases with specific critical points.

Observed continuous vanishing of spin gap and order parameters at phase transitions.

Supported the presence of deconfined quantum critical points.

Abstract

Using the density-matrix renormalization group, we determine the phase diagram of the spin 1/2 Heisenberg antiferromagnet on a honeycomb lattice with a nearest neighbor interaction J1 and a frustrating, next-neighbor exchange J2. As frustration increases, the ground state exhibits Neel, plaquette and dimer orders, with critical points at J2/J1 = 0.22 and 0.35. We observe that both the spin gap and the corresponding order parameters vanish continuously at both the critical points, indicating the presence of deconfined quantum criticality.