Spin dynamics in pressure-induced magnetically-ordered phases in PHCC

TL;DR

This study uses inelastic neutron scattering to investigate how hydrostatic pressure affects the spin excitations in a frustrated quantum magnet, revealing a transition to gapless triplet excitations at 9 kbar due to a change in exchange interactions.

Contribution

It demonstrates the pressure-induced transition to gapless magnetic excitations in PHCC and links this change to a specific exchange pathway modification.

Findings

Magnetic triplet excitations become gapless at 9 kbar.

Pressure alters a key exchange pathway in PHCC.

Results challenge previous reports of gapped excitations under pressure.

Abstract

We present inelastic neutron scattering experiments on the $S=1/2$ frustrated gapped quantum magnet piperazinium hexachlorodicuprate under applied hydrostatic pressure. These results show that at 9 kbar the magnetic triplet excitations in the system are gapless, contrary to what was previously reported. We show that the changes in the excitation spectrum can be primarily attributed to the change in a single exchange pathway.