Distribution of exchange energy in a bond-alternating S=1 quantum spin chain

TL;DR

This paper investigates the distribution of exchange energy in a bond-alternating S=1 quantum spin chain using neutron scattering and numerical methods, revealing details about spin dimerization and ground state modulation.

Contribution

It combines experimental neutron scattering data with numerical DMRG calculations to analyze exchange energy distribution and spin dimerization in NTENP.

Findings

Determined bond-strength alternation parameters from dispersion relations.

Quantified ground state exchange energy modulation via sum rules.

Linked spin dimerization to exchange energy distribution.

Abstract

The quasi-one-dimensional bond-alternating S=1 quantum antiferromagnet NTENP is studied by single crystal inelastic neutron scattering. Parameters of the measured dispersion relation for magnetic excitations are compared to existing numerical results and used to determine the magnitude of bond-strength alternation. The measured neutron scattering intensities are also analyzed using the 1st-moment sum rules for the magnetic dynamic structure factor, to directly determine the modulation of ground state exchange energies. These independently determined modulation parameters characterize the level of spin dimerization in NTENP. First-principle DMRG calculations are used to study the relation between these two quantities.