Strain-induced phase diagram of the $S = \frac32$ Kitaev material $\rm{CrSiTe_3}$

TL;DR

This study maps the quantum phase diagram of a spin-3/2 model related to $ m{CrSiTe_3}$, revealing multiple magnetic phases and first-order transitions, but no evidence of a quantum spin liquid state.

Contribution

It provides the first detailed quantum phase diagram of a spin-3/2 model relevant to $ m{CrSiTe_3}$ using density-matrix renormalization group methods, exploring strain effects on magnetic phases.

Findings

Identified ferromagnetic, 120-degree, and antiferromagnetic phases.

All phases separated by first-order transitions.

No evidence of quantum spin liquid state found.

Abstract

The interplay among anisotropic magnetic terms, such as the bond-dependent Kitaev interactions and single-ion anisotropy, plays a key role in stabilizing the finite-temperature ferromagnetism in the two-dimensional compound $\rm{CrSiTe_3}$. While the Heisenberg interaction is predominant in this material, a recent work shows that it is rather sensitive to the compressive strain, leading to a variety of phases, possibly including a sought-after Kitaev quantum spin liquid [C. Xu, \textit{et. al.}, Phys. Rev. Lett. \textbf{124}, 087205 (2020)]. To further understand these states, we establish the quantum phase diagram of a related bond-directional spin-$3/2$ model by the density-matrix renormalization group method. As the Heisenberg coupling varies from ferromagnetic to antiferromagnetic, three magnetically ordered phases, i.e., a ferromagnetic phase, a $120^\circ$ phase and an antiferromagnetic phase, appear consecutively. All the phases are separated by first-order phase transitions, as revealed by the kinks in the ground-state energy and the jumps in the magnetic order parameters. However, no positive evidence of the quantum spin liquid state is found and possible reasons are discussed briefly.