Raman scattering from turbostratic graphitelike BC4 under pressure

Raman spectra of turbostratic graphitelike BC4(t-BC4) were measured at room temperature and pressures up to 45 GPa on both compression and decompression. At ambient conditions, these Raman spectra contain lines that were not previously observed in Raman spectra of other graphitelike phases. Raman bands of the starting BC4 were assigned on the basis of the lattice dynamics of the ideal graphite structure and relaxation of the q-vector selection rule. The frequency of the E2g(2) in-plane mode at 1561 cm−1 exhibits nonlinear behavior under pressure with the initial pressure coefficient of 7.3 cm−1/GPa. The general behavior of the E2g(2) band at high pressures is consistent with the model of pressure-induced buckling of layers.