Pressure-induced phase transition of one-dimensional semiconductor C5H10NH2PbI3

We studied Raman scattering under hydrostatic pressure for the one-dimensio nal semiconductor C5H10NH2PbI3 up to 2 GPa, and observed a structural phase transition at 0.4 GPa. Raman modes which originate from 6-ring and H-N-C v ibrations of C5H10NH2+ molecules show abrupt changes in their peak position s and linewidths at 0.4 GPa. Narrowing of these modes at the transition pre ssure is Explained by ordering of organic molecules. External phonon modes in the range of 20-200 cm(-1) also change abruptly at about 0.4 GPa. The re sults indicate that this pressure-induced structural phase transition is go verned by rotational and orientational ordering of C5H10NH2+ molecules.