Raman study of κ-ET2Cu[N(CN)2]Cl at ambient and ∼300 bars pressures

Anomalies in the temperature dependence of the 246 and 258 cm−1 Raman active phonons below the antiferromagnetic phase transition are reported in κ-ET2Cu[N(CN)2]Cl at ambient pressure and are compared to measurements under ∼300 bars that render the compound superconducting. At ambient pressure, due to the Mott-gap opening and/or to the spin–lattice interaction and exchange-phonon modulation, frequency softenings, enhanced intensities and linewidths narrowings of these modes occur at low temperatures.