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E. M. Agapov

Publications and source records attributed to E. M. Agapov.

2 recordsLinked to original sources

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

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.

cond-mat.str-el

MXene Fe2C as a promising candidate for the 2D XY ferromagnet

Monolayer Fe$_2$C is expected to possess strong electronic correlations, which can significantly contribute to electronic and magnetic properties. In this work we consider electronic and magnetic properties of MXene Fe$_2$C within the DFT+DMFT approach. We establish the existence of local magnetic moments $μ=3.2μ_B$ in this compound, characterized by sufficiently long lifetime of $τ\sim 350$ fs. We also calculate exchange interaction parameters accounting for electronic correlations using the recently developed approach for paramagnetic phase. We obtain the strongest exchange interaction $11$ meV between next nearest neighboring Fe atoms above (and below) the carbon plane, and the subleading interaction $6$ meV between the next to next nearest neighboring atoms across the carbon plane. The resulting dependence of the Berzinskii-Kosterlitz-Thouless (BKT) and Curie temperatures on magnetic anisotropy is obtained. The BKT temperature for the pristine Fe$_2$C is $T_{\rm BKT}\simeq 290$ K, which makes this compound a good candidate for the two-dimensional ferromagnet with XY anisotropy.

cond-mat.str-el