Stacking-induced magnetic frustration and spiral spin liquid

TL;DR

This paper investigates how stacking arrangements in multilayer triangular lattice antiferromagnets induce magnetic frustration and support a spiral spin liquid phase, revealing a rich phase diagram and robustness of the spin liquid state.

Contribution

It introduces a theoretical framework combining nematic bond theory and Gaussian approximation to analyze stacking-induced magnetic phases in ABC-stacked multilayer magnets.

Findings

Identifies a wide regime of spiral spin liquid with degenerate spiral lines.

Shows the transition from spiral spin liquid to spiral order is first order.

Demonstrates the robustness of the spin liquid phase under small perturbations.

Abstract

Like the twisting control in magic angle twisted bilayer graphenes, the stacking control is another mechanical approach to manipulate the fundamental properties of solids, especially the van der Waals materials. We explore the stacking-induced magnetic frustration and the spiral spin liquid on a multilayer triangular lattice antiferromagnet where the system is built from ABC stacking with competing intralayer and interlayers couplings. By combining the nematic bond theory and the self-consistent Gaussian approximation, we establish the phase diagram for this ABC-stacked multilayer magnet. It is shown that, the system supports a wide regime of spiral spin liquid with multiple degenerate spiral lines in the reciprocal space, separating the low-temperature spiral order and the high-temperature featureless paramagnet. The transition to the spiral order from the spiral spin liquid regime is first order. We further show that the spiral-spin-liquid behavior persists even with small perturbations such as further neighbor intralayer exchanges. The connection to the ABC-stacked magnets, the effects of Ising or planar spin anisotropy, and the outlook on the stacking-engineered quantum magnets are discussed.