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Recent syntheses of the potential room-temperature 2D ferromagnet CrTe2 as thin flakes or monolayers have shown either in-plane [1–4] and out-of-plane easy axes [5–7]. To understand this discrepancy, we have calculated the magnetic anisotropy energy (MAE) for bulk and monolayer systems in the first-principles density functional theory. The calculated energy difference between out-of-plane and in-plane magnetization is much larger than that within the 2D plane, in good agreement with previous work [8, 9]. However, the magnitude and sign of the MAE are very sensitive to the lattice constant and jellium doping level, which explains the discrepancy and suggests that we can potentially tune the easy axis through strain and gating.

[1]  X. Sun et al., Nano Res. 13, 3358 (2020)

[2]  F. Fabre et al., Phys. Rev. Materials 5, 034008 (2021)

[3]  A. Purbawati et al., ACS Appl. Mater. Interfaces 12, 30702 (2020)

[4]  D. C. Freitas et al., J. Phys.: Condens. Matter 27, 176002 (2015)

[5]  X. Zhang et al., Nat Commun 12, 2492 (2021)

[6]  L. Meng et al., Nat Commun 12, 809 (2021)

[7]  Y. Ou et al., http://arxiv.org/abs/2107.08599

[8]  S. Li et al., Phys. Rev. B 103, 045114 (2021)

[9]  X. Yang et al., Phys. Rev. B 103, 024436 (2021)