Raman study of the structural transition in LiVO$_2$

TL;DR

This study uses polarization-dependent Raman spectroscopy to investigate the structural transition in LiVO$_2$, revealing lattice reconstruction and symmetry details associated with its transition to a diamagnetic state below 500K.

Contribution

It provides experimental evidence of lattice reconstruction and symmetry constraints in LiVO$_2$ during its phase transition, supported by DFT calculations.

Findings

Detection of new Raman peaks below 500K

Confirmation of    lattice reconstruction

Possible stacking faults indicated by thermal cycling study

Abstract

The results of polarization-dependent Raman spectroscopy of single-crystalline LiVO$_2$ exhibiting transition to a diamagnetic state below $T_c \sim $500K are reported. Our measurements clearly detect additional peaks in the low-temperature phase, which disappear nearly completely when heated above $T_c$. Proposed $\sqrt{3}$a \times $\sqrt{3}$a lattice reconstruction explains these new Raman peaks by the Brillouin zone folding. The experiment, on the one hand, confirms that the symmetry of the non-magnetic phase is not lower than trigonal, but, on another 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 1 K per formula unit.