Evolution of the thermodynamic properties and inelastic neutron scattering intensities for spin-1/2 antiferromagnetic quantum rings

TL;DR

This paper investigates how the magnetic properties and inelastic neutron scattering intensities evolve in small spin-1/2 quantum rings with varying interactions, revealing complex ground states and spin-mixing effects through exact diagonalization.

Contribution

It provides a detailed analysis of the thermodynamic and scattering properties of quantum rings, including closed-form expressions and the impact of crossing interactions, advancing understanding of their magnetic behavior.

Findings

Complex spin-mixing and multiple ground states identified.

Closed-form expressions for energy eigenstates and structure factors.

Crossing interactions significantly affect thermodynamic properties.

Abstract

This study examines the increasing complexity in the magnetic properties of small $n$ = 3, 4, 5, 6 spin-1/2 quantum rings. Using an exact diagonalization of the isotropic Heisenberg Hamiltonian with nearest and next-nearest neighbor interactions, the energy eigenstates, magnetic specific heat capacity, magnetic susceptibility, and inelastic neutron scattering structure factors are determined for variable next-nearest neighbor interactions. Here, it is shown that the presence of a complex spin-mixing, multiple ground states, and non-zero ground states greatly complicate the spin Hamiltonian. Overall, the energy eigenstates and structure factor intensities are presented in closed form, while the thermodynamic properties detail the effect of a crossing interaction in the rings. The goal of this work is to provide insight into the evolution of the magnetic properties and spin excitations within these systems.