Physical review. B./Physical review. B
Quantum order by disorder in frustrated spin nanotubes
João C. Getelina, Zekun Zhuang, Premala Chandra, Piers Coleman, Peter P. Orth, Shivaji L. Sondhi
Abstract
We investigate quantum order by disorder in a frustrated spin nanotube formed by wrapping a ${J}_{1}\text{\ensuremath{-}}{J}_{2}$ Heisenberg model at ${45}^{\ensuremath{\circ}}$ around a cylinder. Using Schwinger boson theory and density matrix renormalization group (DMRG), we have computed the ground-state phase diagram to reveal a ${\mathbb{Z}}_{2}$ phase in which collinear spin stripes form a right- or left-handed helix around the nanotube. We have derived an analytic estimate for the critical ${\ensuremath{\eta}}_{c}={J}_{1}/2{J}_{2}$ of the ${\mathbb{Z}}_{2}$-helical phase transition, which is in agreement with the DMRG results. By evaluating the entanglement spectrum and nonlocal string order parameters we discuss the topology of the ${\mathbb{Z}}_{2}$-helical phase.