Candidate quantum disordered intermediate phase in the Heisenberg antiferromagnet on the maple-leaf lattice

TL;DR

This study investigates the ground state phases of the spin-1/2 Heisenberg antiferromagnet on the maple-leaf lattice, revealing a quantum spin liquid phase between ordered and valence bond crystal states, using advanced renormalization group techniques.

Contribution

It provides the first evidence of a quantum spin liquid phase in this lattice model, suggesting proximity to a deconfined quantum critical point and demonstrating the effectiveness of pseudo-fermion functional renormalization group methods.

Findings

Identification of a QSL regime between magnetic and valence bond crystal phases

Finite-size scaling confirms the stability of the QSL phase

Potential tuning of exchange couplings could access the QSL state

Abstract

Quantum antiferromagnets on geometrically frustrated lattices have long attracted interest for the formation of quantum disordered states and the possible emergence of quantum spin liquid (QSL) ground states. Here we turn to the nearest-neighbor spin-$1/2$ Heisenberg antiferromagnet on the maple-leaf lattice, which is known to relieve frustration by the formation of canted $120^{\circ}$ magnetic order or valence bond crystal order when varying the bond anisotropy. Employing a pseudo-fermion functional renormalization group approach to assess its ground state phase diagram in detail, we present evidence for a QSL regime sandwiched between these two limiting phases. The formation of such a QSL might signal proximity to a possible deconfined quantum critical point from which it emerges, and that is potentially accessible by tuning the exchange couplings. Our conclusions are based on large-scale simulations involving a careful finite-size scaling analysis of the behavior of magnetic susceptibility and spin-spin correlation functions under renormalization group flow.