Quantum Phases in the Honeycomb-Lattice $J_1$--$J_3$ Ferro-Antiferromagnetic Model

TL;DR

This study uses advanced computational methods to reveal that the quantum $J_1$--$J_3$ honeycomb lattice model exhibits novel phases, including double-zigzag and Ising-z, which differ significantly from classical predictions.

Contribution

It introduces a comprehensive quantum phase diagram for the $J_1$--$J_3$ honeycomb model, identifying unexpected collinear phases that replace classical spiral states.

Findings

Discovery of double-zigzag and Ising-z phases as quantum intermediaries

Quantum phases extend beyond classical stability regions

Replacement of classical spiral state by collinear phases

Abstract

Using large-scale density-matrix renormalization group calculations and minimally augmented spin-wave theory, we demonstrate that the phase diagram of the quantum $S\!=\!\frac12$ $J_1$--$J_3$ ferro-antiferromagnetic model on the honeycomb lattice differs dramatically from the classical one. It hosts the double-zigzag and Ising-z phases as unexpected intermediaries between ferromagnetic and zigzag states that are also extended beyond their classical regions of stability. In broad agreement with quantum order-by-disorder arguments, these collinear phases replace the classical spiral state.