# Quantum Spin Hall-like Phononic States in van der Waals Bilayers with Antiferromagnetic Ordering

## TL;DR

This paper proposes a new class of phononic states in van der Waals bilayers with antiferromagnetic order, exhibiting quantum spin Hall-like properties with edge modes, expanding topological phononics.

## Contribution

It introduces quantum spin Hall-like phononic states in bilayer systems with antiferromagnetic order, demonstrating their existence in experimentally relevant materials like bilayer CrI3.

## Key findings

- Quantum spin Hall-like phononic states are predicted in van der Waals bilayers.
- Chiral edge modes are spatially separated in these states.
- The states are demonstrated in bilayer CrI3 with antiferromagnetic order.

## Abstract

Here, we propose quantum spin Hall-like phononic states in van der Waals bilayer systems with antiferromagnetic ordering. Antiferromagnetic ordering in bilayer systems with small interlayer interaction makes the total Chern number zero, where the Chern numbers for each layer are opposite to each other. In bilayer CrI3 where antiferromagnetic ordering has been experimentally demonstrated, we show that the quantum spin Hall-like states appear with spatially separated chiral edge modes.