Raman active high energy excitations in URu2Si2

Abstract

We have performed Raman scattering measurements on URu2Si2 single crystals on a large energy range up to ∼1300 cm−1 and in all the Raman active symmetries as a function of temperature down to 15 K. A large excitation, active only in the Eg symmetry, is reported. It has been assigned to a crystal electric field excitation on the Uranium site. We discuss how this constrains the crystal electric field scheme of the Uranium ions. Furthermore, three excitations in the A1g symmetry are observed. They have been associated to double Raman phonon processes consistently with ab initio calculations of the phonons dispersion.