Can the highly symmetric SU(4) spin-orbital model be realized in alpha-ZrCl3?

TL;DR

This study investigates whether alpha-ZrCl3 can realize the SU(4) spin-orbital model, finding that it likely dimerizes and thus does not exhibit the symmetric magnetic properties expected from the model.

Contribution

The paper provides first-principles calculations showing alpha-ZrCl3's tendency to dimerize, challenging its suitability as a realization of the SU(4) spin-orbital model.

Findings

Alpha-ZrCl3 likely dimerizes at normal conditions.

Dimerization leads to a non-magnetic ground state.

Small energy differences suggest possible dimer mobility.

Abstract

We study physical properties of a potential candidate for the physical realization of the SU(4) spin-orbital model - layered alpha-ZrCl3. Both DFT and DFT+U+SOC calculations show that this material most probably dimerizes at normal conditions. Therefore it is unlikely that symmetric SU(4) model can be used for description of magnetic properties of alpha-ZrCl3 at low temperatures. In the dimerized structure electrons occupy molecular orbitals formed by the xy orbitals. One might expect a non-magnetic ground state in this case. Interestingly the energy difference between various dimers packings is rather small and thus dimers may start to flow over the lattice as they do in Li2RuO3.