Electronic structure of the delafossite-type CuMO_2 (M = Sc, Cr, Mn, Fe, and Co): Optical absorption measurements and first-principles calculations

摘要

We compared the results of first-principles calculations with measured absorption spectra in thin films of delafossite-type CuMO_2 (M = Sc, Cr, Mn, Fe, and Co) taken at 10 K. Two optical transitions were found: one is associated with Cu3rf + O2p→ Cu3d_z~2 + 4s observed in all of the CuMO_2 films, and the other is associated with Cu3d + O2p → M3d detected for M = Mn, Fe, and Co. The energy of the former transition showed an unexpected dependence on the atomic number of M. An abrupt change of this energy occurs for M = Cr, which is explained as a result of the interaction between the Cu3d_Z~2 + 4s and M3d bands.