# Frustrated honeycomb-lattice bilayer quantum antiferromagnet in a magnetic field

## TL;DR

This paper investigates the low-temperature thermodynamic properties of a frustrated honeycomb-lattice bilayer quantum antiferromagnet in a magnetic field, revealing a finite-temperature phase transition through theoretical and computational methods.

## Contribution

It introduces an effective low-energy theory for the frustrated bilayer system and analyzes its thermodynamic behavior using exact diagonalizations and quantum Monte Carlo simulations.

## Key findings

- Identification of a finite-temperature phase transition at high magnetic fields.
- Detailed magnetization curve behavior at low temperatures.
- Temperature dependence of the specific heat indicating phase transition.

## Abstract

Frustrated bilayer quantum magnets have attracted attention as flat-band spin systems with unconventional thermodynamic properties. We study the low-temperature properties of a frustrated honeycomb-lattice bilayer spin-$\frac{1}{2}$ isotropic ($XXX$) Heisenberg antiferromagnet in a magnetic field by means of an effective low-energy theory using exact diagonalizations and quantum Monte Carlo simulations. Our main focus is on the magnetization curve and the temperature dependence of the specific heat indicating a finite-temperature phase transition in high magnetic fields.