The nature of excitations in a molecular Haldane system


It is well known that an S = 1 antiferromagnetic spin chain is predicted to have a quantum disordered ground state and a gap in its excitation spectrum. This so-called Haldane gap is topological in origin and contrasts dramatically with the case for S = 1/2, whose topology leads to a gapless spectrum. We have recently synthesised an intriguing new series based on S = 1 NiX2(3,5-lutidine)4 molecular complexes formed from quasi-one-dimensional columns of Ni-X...X-Ni. In an experiment at PSI in 2017 we showed that NiI2(3,5-lutidine)4 remains disordered down to 30 mK, suggesting that the system is a highly successful realization of a Haldane chain system. We now plan to investigate the order and dynamics of the system in high field as we close the spin gap and drive the system through a quantum critical point (QCP) in a new experiment, only possible using the HIFI spectrometer at ISIS.

Metadata Access
Creator Professor Stephen Blundell; Dr Murray Wilson; Dr Mark Telling; Dr Matjaz Gomilsek; Professor Tom Lancaster; Dr Francis Pratt; Dr Ben Huddart; Professor Jamie Manson; Dr Thomas Hicken
Publisher ISIS Neutron and Muon Source
Publication Year 2023
Rights CC-BY Attribution 4.0 International;
OpenAccess true
Contact isisdata(at)
Resource Type Dataset
Discipline History; Humanities; Natural Sciences; Physics
Temporal Coverage Begin 2020-02-13T08:30:00Z
Temporal Coverage End 2020-02-24T08:41:16Z