Exploitable Magnetic Anisotropy of the Two-Dimensional Magnet CrI₃

Abstract

Magnetic anisotropy often plays a central role in various static and dynamic properties of magnetic materials. In particular, for two-dimensional (2D) van der Waals materials, as inferred from the Mermin–Wagner theorem, it is an essential prerequisite for stabilizing ferromagnetic order. In this work, we carry out first-principles calculations for a CrI3 monolayer and investigate how its magnetic anisotropy is interrelated to adjustable parameters governing the underlying electronic structure. We explore various routes for controlled manipulation of magnetic anisotropy: chemical adsorption, substitutional doping, optical excitation, and charge transfer through a heterostructure. In particular, the vertical stacking of CrI3 and graphene is noteworthy in regard to controlling magnetic anisotropy: the spin anisotropy axis is switchable between the out-of-plane and in-plane directions, which is accompanied by a variation in the anisotropy energy of up to 500%. Our results show the possibility that dynamic control of the anisotropy of the 2D magnet CrI3 may enable the development of an advanced spintronic device with enhanced energy efficiency and high operation speed.

Valence band electronic structure of the van der Waals ferromagnetic insulators: VI$$_3$$ and CrI$$_3$$

“…In addition, above those, the three more bands can now be identified more clearly. These three bands are mainly of I 5p character 17,19,45,46 around Ŵ and agree moderately with the bands calculated using the generalized gradient approximation (GGA) and accounting for the SOC and the ferromagnetic ground state with the out-of-plane moments 17,45 . The calculated bands 17,45 with antiferromagnetic and non-magnetic ground states do not agree with the experimental results.…”

“…The ARPES spectra are intrinsically broad due to the existence of a large number of overlapping bands 44 and a relatively high temperature of the measurements. The broad, less dispersive features at 2.5 eV are mainly of Cr 3 d character, according to calculations 45 , 46 . Around the point, within the energy range 1.3–2.1 eV, a strongly dispersive feature is attributed to iodine 5 p orbital 45 , 46 .…”

“…The broad, less dispersive features at 2.5 eV are mainly of Cr 3 d character, according to calculations 45 , 46 . Around the point, within the energy range 1.3–2.1 eV, a strongly dispersive feature is attributed to iodine 5 p orbital 45 , 46 . In iso-energy contour, this band forms a hole-like circular feature, centered at , as shown in Fig.…”

“…Their results show that a monolayer and bulk have very similar partial- and total DOS but the relative contributions within the DOS and energy positions differ significantly between the two methods. Orbital resolved band dispersions for a monolayer CrI is reported by Jiang et al 45 and Kim et al 46 . They show that the the valence band maximum (VBM) is dominated by I 5 p orbitals (mainly and ) and have also discussed the effects of SOC in the band dispersions.…”

Impact of oxygen defects on a ferromagnetic CrI3 monolayer

“…As can be seen, both the CBM and VBM occurs at the G-point of Brillouin zone, showing a semiconducting behaviour with the direct bandgap of 1.14 eV that is consistent with the previously reported results. [24][25][26] Fig. 5b presents the spindependent electronic band structure of the O-attached CrI 3 monolayer.…”