Excitation-dependent Raman spectra in hexaborides – Surface phonons of LaB6

Excitation-dependent Raman spectra of hexaborides are systematically analyzed. Excitation energies below the plasma edge yield the spectra of surface phonons. The most prominent features in the accordingly obtained surface spectrum of LaB6 are due to the metal atoms in the uppermost atomic layer of the [001] face and to the layer of distorted octahedra immediately below.

Graphical abstract[001] surface phonon spectrum of LaB6.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Excitation energy dependent Raman spectra of hexaborides are analyzed. ► Surface phonon spectrum of LaB6 is determined. ► Surface phonon modes of LaB6 are discussed with respect to theory and other methods.