Neutron scattering study of a quasi-2D spin-1/2 dimer system Piperazinium Hexachlorodicuprate under hydrostatic pressure

TL;DR

This study uses inelastic neutron scattering to investigate how hydrostatic pressure affects the spin gap and excitations in a quasi-2D S=1/2 dimer system, revealing pressure-induced softening of the spin gap.

Contribution

It provides the first detailed experimental analysis of pressure effects on the spin excitations in Piperazinium Hexachlorodicuprate, confirming theoretical predictions.

Findings

Spin gap decreases from 1.0 meV to 0.55 meV at 9.0 kbar

Triplet excitation degeneracy observed at 6.0 kbar

Bandwidth remains unchanged within experimental uncertainty

Abstract

We report inelastic neutron scattering study of a quasi-two-dimensional S=1/2 dimer system Piperazinium Hexachlorodicuprate under hydrostatic pressure. The spin gap {\Delta} becomes softened with the increase of the hydrostatic pressure up to P= 9.0 kbar. The observed threefold degenerate triplet excitation at P= 6.0 kbar is consistent with the theoretical prediction and the bandwidth of the dispersion relation is unaffected within the experimental uncertainty. At P= 9.0 kbar the spin gap is reduced to 0.55 meV from 1.0 meV at ambient pressure.