Thermodynamics of the Heisenberg antiferromagnet on the maple-leaf lattice

Abstract We study the Heisenberg antiferromagnet on the maple-leaf lattice using several numerical approaches, focusing on the numerical linked-cluster expansion (NLCE), which exhibits an unconventional convergence extending to low and even zero temperatures. We evaluate thermodynamic properties as well as spin–spin correlations through the equal-time structure factor. Within NLCE, the specific heat capacity reveals a two-peak structure at T 1 ≈ 0.479 J and T 2 ≈ 0.131 J, reminiscent of the corresponding result for the triangular lattice. At intermediate temperatures, the spin–spin structure factor develops features that reflect the absence of reflection symmetry in the lattice. The zero-temperature convergence of NLCE enables reliable estimates of the ground-state energy and points to a short-range correlated paramagnetic ground state composed of resonating hexagonal motifs. The NLCE results are benchmarked against pseudo-Majorana functional renormalization group, finite-temperature Lanczos, and classical Monte Carlo simulations.