Anisotropic optical conductivity of RPtAs (R = La, Ce)

The origins of the anisotropic physical properties of CePtAs and LaPtAs wer e investigated by the optical conductivity and the XPS measurements. Optica l conductivity spectra indicate that the property parallel to the c-axis is semiconducting and that perpendicular to the c-axis is metallic both for C ePtAs and LaPtAs. The spectral features due to the pf mixing also show the anisotropic nature of CePtAs, namely, the intensity perpendicular to c-axis is stronger than that along c-axis. (C) 1999 Elsevier Science B.V. All rig hts reserved.