Raman Study of (LaBa)2CuO4 Single Crystals

Abstract
Raman scattering of La2-x Ba x CuO4 (x=0, 0.016) single crystals at various temperatures has been studied for the frequency range between 100 and 5000 cm-1. Besides an A1g phonon peak at 430 cm-1, the 480 and 725 cm-1 peaks are ascribed to the disorder-induced phonon modes which are allowed by the breakdown of lattice translational symmetry. The 940, 1220, and 1445 cm-1 peaks are thought to be the phonon overtone and combination modes. A two-magnon peak observed at 2900 cm-1 at room temperature in a La1.984Ba0.016CuO4 sample with fresh surfaces is also discussed.