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

摘要

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