Emergent interacting spin islands in a depleted strong-leg Heisenberg ladder

TL;DR

This study investigates how disorder in a depleted strong-leg Heisenberg ladder material leads to emergent, strongly interacting spin island objects, with their structure and interactions characterized through neutron spectroscopy.

Contribution

The paper provides the first detailed experimental characterization of the structure and interactions of emergent spin islands in a depleted Heisenberg ladder.

Findings

Identification of the spatial shape of spin islands

Observation of strong mutual interactions among spin islands

Detection of in-gap spectral contributions indicating interactions

Abstract

Properties of the depleted Heisenberg spin ladder material series (C$_7$H$_{10}$N)$_2$Cu$_{1-z}$Zn$_{z}$Br$_4$ have been studied by the combination of magnetic measurements and neutron spectroscopy. Disorder-induced degrees of freedom lead to a specific magnetic response, described in terms of emergent strongly interacting "spin island" objects. The structure and dynamics of the spin islands is studied by high-resolution inelastic neutron scattering. This allows to determine their spatial shape and to observe their mutual interactions, manifested by strong spectral in-gap contributions.