Frustrated Quantum Antiferromagnets: Application of High-Order Coupled Cluster Method

TL;DR

This paper applies high-order coupled cluster methods to study frustrated quantum antiferromagnets across different dimensions, revealing quantum phase transitions and ground states with high precision.

Contribution

It demonstrates the effectiveness of high-order coupled cluster methods in analyzing quantum phase transitions and ground states in various frustrated antiferromagnetic models.

Findings

Accurate energy, magnetization, and spin stiffness calculations for cubic lattice antiferromagnets.

Insights into quantum fluctuations and interchain effects on incommensurate spiral states.

Identification of quantum paramagnetic phases influenced by interlayer coupling.

Abstract

We report on recent results for strongly frustrated quantum $J_1$-$J_2$ antiferromagnets in dimensionality d=1,2,3 obtained by the coupled cluster method (CCM). We demonstrate that the CCM in high orders of approximation allows us to investigate quantum phase transitions driven by frustration and to discuss novel quantum ground states. In detail we consider the ground-state properties of (i) the Heisenberg spin-1/2 antiferromagnet on the cubic lattice in d=1,2,3, and use the results for the energy, the sublattice magnetization and the spin stiffness as a benchmark test for the precision of the method; (ii) coupled frustrated spin chains (the quasi-one-dimensional $J_1$--$J_2$ model) and discuss the influence of the quantum fluctuations and the interchain coupling on the incommensurate spiral state present in the classical model; (iii) the Shastry-Sutherland antiferromagnet on the square lattice; and (iv) a stacked frustrated square-lattice Heisenberg antiferromagnet (the quasi-two-dimensional $J_1$--$J_2$ model), and discuss the influence of the interlayer coupling on the quantum paramagnetic ground-state phase that is present for the strictly two-dimensional model.