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Magnetic properties of monolayer, multilayer, and bulk CrTe$_2$

A. A. Katanin, E. M. Agapov

Abstract

We investigate magnetic properties of CrTe$_2$ within the density functional theory (DFT) approach in ferromagnetic phase and combination of DFT and dynamical mean field theory (DFT+DMFT) approach in paramagnetic phase. We show that few layer CrTe$_2$ possesses well formed local magnetic moments. In the single layer CrTe$_2$ we find antiferromagnetic exchange with 120\degree antiferromagnetic structure most preferable. In the bilayer and trilayer systems electronic correlations in DFT+DMFT approach yield ferromagnetic exchange interaction within each layer, but the interaction between the layers is antiferromagnetic, such that alternation of the direction of magnetization of the layers is expected. In bulk CrTe$_2$ we find the tendency to ferromagnetic order at low temperature, but with increase of temperature antiferromagnetic correlations between the layers dominate. Determination of the critical number of layers at which the interlayer antiferromagnetic order changes to the ferromagnetic one, likely requires consideration of the non-local Coulomb interactions. Erratum: In our study [A. A. Katanin, E. M. Agapov, Phys. Rev. B 111, 035118 (2025)] we found for the monolayer CrTe$_2$ the most preferable 120\degree spin spiral structure. While this order is expected for freely suspended CrTe$_2$, for experimentally realized single layer CrTe$_2$ on a substrate, which is characterized by larger lattice constant, the momentum dependence of the susceptibilities drastically changes. In particular, the ferromagnetic ground state is expected for this compound, in agreement with the experimental data.

Magnetic properties of monolayer, multilayer, and bulk CrTe$_2$

Abstract

We investigate magnetic properties of CrTe within the density functional theory (DFT) approach in ferromagnetic phase and combination of DFT and dynamical mean field theory (DFT+DMFT) approach in paramagnetic phase. We show that few layer CrTe possesses well formed local magnetic moments. In the single layer CrTe we find antiferromagnetic exchange with 120\degree antiferromagnetic structure most preferable. In the bilayer and trilayer systems electronic correlations in DFT+DMFT approach yield ferromagnetic exchange interaction within each layer, but the interaction between the layers is antiferromagnetic, such that alternation of the direction of magnetization of the layers is expected. In bulk CrTe we find the tendency to ferromagnetic order at low temperature, but with increase of temperature antiferromagnetic correlations between the layers dominate. Determination of the critical number of layers at which the interlayer antiferromagnetic order changes to the ferromagnetic one, likely requires consideration of the non-local Coulomb interactions. Erratum: In our study [A. A. Katanin, E. M. Agapov, Phys. Rev. B 111, 035118 (2025)] we found for the monolayer CrTe the most preferable 120\degree spin spiral structure. While this order is expected for freely suspended CrTe, for experimentally realized single layer CrTe on a substrate, which is characterized by larger lattice constant, the momentum dependence of the susceptibilities drastically changes. In particular, the ferromagnetic ground state is expected for this compound, in agreement with the experimental data.
Paper Structure (6 sections, 3 equations, 15 figures, 1 table)

This paper contains 6 sections, 3 equations, 15 figures, 1 table.

Table of Contents

  1. Introduction
  2. Methods and parameters
  3. Results
  4. Conclusions
  5. Monolayer band structure in the ferromagnetic phase
  6. Energy mapping of monolayer system

Figures (15)

  • Figure 1: (Color online) Band structure (a) and DFT density of states (b) of the monolayer CrTe$_2$ in paramagnetic phase. The inset in (a) shows the DFT Fermi surface; the arrow shows the nesting vector which is close to ${\mathbf Q}_K=\overrightarrow{\Gamma K}$.
  • Figure 2: Imaginary part of the self-energy of various orbital combinations of monolayer (blue solid symbols) and bilayer (green open symbols) CrTe$_2$ at the imaginary frequency axis in DFT+DMFT approach at $\beta=18$ eV$^{-1}$ ($T=645$ K).
  • Figure 3: Momentum dependence of the orbital-summed susceptibility of the monolayer CrTe$_2$ in DFT+DMFT approach at $\beta=7$ eV$^{-1}$ ($T=1660$ K).
  • Figure 4: (Color online) Inverse uniform and staggered, ${\mathbf Q}={\mathbf Q}_K$ (a) and local (b) spin susceptibility of the monolayer CrTe$_2$ in DFT+DMFT approach. Dashed lines show extrapolation to the low-temperature region.
  • Figure 5: (Color online) Exchange interaction in monolayer CrTe$_2$ at $\beta=20$ eV$^{-1}$ ($T=580$ K). Red solid line (squares) corresponds to DFT+DMFT approach in paramagnetic phase, blue dashed line (filled triangles) is the result of the DFT approach in FM phase. For comparison, the result of DFT approach at $\beta=10$ eV$^{-1}$ ($T=1160$ K) is shown by dot-dashed violet line with open triangles
  • ...and 10 more figures