J.A. Henao

Raman spectra of Cu2BIICIV X4VI magnetic quaternary semiconductor compounds with tetragonal stannite type structure

A comparative study of the Raman spectra of Cu2BIICIV S4VI and Cu2BIICIV Se4VI(where B = Mn or Fe) magnetic quaternary semiconductor compounds with stannite-type structure (I 4¯2m) has been done. Most of the fourteen Raman lines expected for these materials were observed in the spectra. The two strongest lines observed have been assigned to the IR inactive A11 and A12 stannite modes that originated from the motion of the S or Se anion around the Cu and CIV cations remaining at rest. The shift in the frequency of these two lines of about 150 cm−1 to lower energies observed in Cu2BIICIV Se4VI compounds as compared to those in Cu2BIICIV S4VI ones, can then be explained as due to the anion mass effect. Based on the fact that values of these frequencies depend mainly on anion mass and bond-stretching forces between nearest-neighbor atoms, the vibrational frequencies v¯(A12) and v¯(A12) of both modes for several Cu2BIICIV X4VI stannite compounds (where X = S, Se, or Te) very close to the experimental data repor...