Raman scattering study under pressure at 6 K of the N = 4 incommensurate phase II of biphenyl

Abstract
Pressure lowers the domain of existence of the incommensurate phase II of biphenyl. This allows a study of the characteristic dynamics of an incommensurate phase with n = 4 in optimal conditions i.e. at very low temperature. Raman scattering in such extremal conditions have allowed to give complementary results with respect to previous neutron scattering experiments and so to extend the knowledge of the characteristic phason and amplitudon branches by investigating a larger range of frequency with a good resolution.