Local symmetry breaking in Eu1-xLaxB6

Abstract

We report inelastic light (Raman) scattering study of Eu1-xLa xB6 (x = 0, 0.05, 0.1, 0.2, 0.3). As La is doped, the T2g mode becomes broad and asymmetric, the Eg mode splits into doublet, and the A1g mode shifts to higher frequencies, while the undoped EuB6 show sharp three phonon peaks, T2g, Eg, and A1g modes. There are around six possible phonon peaks in the Raman spectra of La-doped EuB6. These additional peaks are explained by symmetry lowering of boron octahedra due to tilting/rotating. © 2006.