Crystal field states ofTb3+in the pyrochlore spin liquidTb2Ti2O7from neutron spectroscopy

Abstract

We report time-of-flight neutron scattering measurements of the magnetic spectrum of ${\mathrm{Tb}}^{3+}$ in ${\mathrm{Tb}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$. The data, which extend up to 120 meV and have calibrated intensity, enable us to consolidate and extend previous studies of the single-ion crystal field spectrum. We successfully refine a model for the crystal field potential in ${\mathrm{Tb}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$ without relying on data from other rare-earth titanate pyrochlores, and we confirm that the ground state is a non-Kramers doublet with predominantly $|\ifmmode\pm\else\textpm\fi{}4\ensuremath{\rangle}$ components. We compare the model critically with earlier models.