Thermodynamics of the spin-1/2 Heisenberg antiferromagnet on the star lattice

TL;DR

This paper investigates the thermodynamic behavior of the spin-1/2 Heisenberg antiferromagnet on the star lattice using advanced computational methods, revealing insights into phase diagrams, comparison with other frustrated systems, and experimental relevance.

Contribution

It introduces a comprehensive study combining multiple simulation techniques to analyze the thermodynamics of the star lattice antiferromagnet, including phase diagram exploration and comparison with experimental data.

Findings

Identification of thermodynamic properties across parameter regimes

Comparison of cluster decoupling schemes for quantum Monte Carlo

Relation of results to experimental Cu-based compounds

Abstract

Using a combination of quantum Monte Carlo simulations in adapted cluster bases, the finite temperature Lanczos method, and an effective Hamiltonian approach, we explore the thermodynamic properties of the spin-1/2 Heisenberg antiferromagnet on the star lattice. We consider various parameter regimes on this strongly frustrated Archimedean lattice, including the case of homogeneous couplings as well as the distinct parameter regimes of dominant vs. weak dimer coupling. For the latter case, we explore the quantum phase diagram in the presence of inhomogeneous trimer couplings, preserving inversion symmetry. We compare the efficiency of different cluster decoupling schemes for the quantum Monte Carlo simulations in terms of the sign problem, contrast the thermodynamic properties to those of other strongly frustrated quantum magnets, such as the kagome lattice model, and comment on previous results from tensor-network calculations regarding a valence bond crystal phase in the regime of weak dimer coupling. Finally, we relate our results to recently reported experimental findings on a Cu-based quantum magnetic spin-1/2 compound with an underlying star lattice structure.