Valence bond solid and possible deconfined quantum criticality in an extended kagome lattice Heisenberg antiferromagnet

Understand

We present numerical evidence for the emergence of an extended valence bond solid (VBS) phase at $T=0$ in the kagome $S=1/2$ Heisenberg antiferromagnet with ferromagnetic further-neighbor interactions.

• The VBS is located at the boundary between two magnetically ordered regions and extends close to the nearest-neighbor Heisenberg point.
• It exhibits a diamond-like singlet covering pattern with a $12$-site unit-cell.
• Our results suggest the possibility of a direct, possibly continuous, quantum phase transition from the neighboring $\mathbf{q}=0$ coplanar magnetically ordered phase into the VBS phase.