Raman study of the structural transition in LiVO2

The results of polarization-dependent Raman spectroscopy of single-crystalline LiVO2 exhibiting transition to a diamagnetic state below Tc∼500K are reported. Our measurements clearly detect additional peaks in the low-Temperature phase, which disappear nearly completely when heated above Tc. Proposed 3a×3a lattice reconstruction explains these new Raman peaks by the Brillouin zone folding. The experiment, on the one hand, confirms that the symmetry of the nonmagnetic phase is not lower than trigonal, but, on the other hand, our thermal cycling study suggests possible stacking faults. This agrees with results of the density functional theory calculations, which show that the energy difference between different types of stacking does not exceed 1K per formula unit. © 2024 American Physical Society.