Ferromagnetic and Antiferromagnetic Magnons in Cr₂C MXenes

The synthesis of 2D materials has boosted the study of magnetic properties in two dimensions¹. As an example, Cr-based structures (e.g., CrI₃) allow for the realization of different magnetic orderings², and topological magnons³. In this work, we study the MXenes Cr₂C magnetic material via the spin-spin Heisenberg Hamiltonian including exchange interactions between first, second and third neighbors and Zeeman interaction. Previous DFT calculations showed that different Cr₂C functionalization leads to different magnetic orderings, including one ferromagnetic (FM) and three antiferromagnetic (AFM) configurations². Here we calculate the magnon dispersion relations for all four magnetic orderings using the Holstein-Primakoff and obtain magnons group velocities larger than the ones in CrI₃. In addition, we also study the corresponding magnon thermal Hall conductivity as a function of temperature and magnetic field.

References

¹Gong, Cheng, and Xiang Zhang. "Two-dimensional magnetic crystals and emergent heterostructure devices." Science363.6428 (2019): eaav4450.

²Yogendra Limbu, Hari Paudyal, Denis R. Candido, Michael E. Flatté and Durga Paudyal. To be submitted.

³Costa, António T., et al. "Topological magnons in CrI₃ monolayers: an itinerant fermion description." 2D Materials 7.4 (2020): 045031.