Crystal Field Levels in Cerium Hafnate: a New Quantum Spin Liquid

A theoretically predicted Octupolar QSI was found in the Ce2Sn2O7 pyrochlore oxide. The presence of a dipole-octupole ground state doublet explains remarkably well macroscopic measurements and crystal-field analysis. Furthermore, the octupolar nature of the correlations has been observed, taking the shape of a broad hump located at high momentum transfer in neutron diffraction patterns. Unfortunately, the chemistry of Ce2Sn2O7 makes it challenging to grow single crystals to further elucidate the nature of its ground state. However, it is possible for its parent compound, Ce2Hf2O7. Its chemical and physical similarities with Ce2Sn2O7 motivate its investigation as it could withstand undoubtable fingerprints of this Octupolar QSI. We propose to probe Ce2Hf2O7 crystal field levels of as they play a crucial role in determining the system’s ground state wavefunction and to its understanding.