Doping enhanced ferromagnetism and induced half
metallicity in CrI3 monolayer
Hongbo Wang, Fengren Fan, Shasha Zhu, and Hua
*
Wu
Laboratory for Computational Physical Sciences, State Key Laboratory of Surface Physics, and Department
of Physics, Fudan University, Shanghai, China
Abstract
Two dimensional materials are of current great interest for their promising applications to postsilicon
microelectronics. Here we study, using first-principles calculations and a Monto Carlo simulation, the electronic
structure and magnetism of CrI3 monolayer. Our results show that CrI3 monolayer remains ferromagnetic (FM) with
TC∼75K, and the FM order is due to a superexchange in the near 90◦ Cr-I-Cr bonds. Moreover, we find that hole doping
is three times as fast as electron doping in increasing TC, and a room temperature FM half metallicity could be achieved
in CrI3 monolayer via a half hole doping. Therefore, CrI3 monolayer would be an appealing two dimensional spintronic
material.
Results and Discussion
FIG. 3. Specific heat curves for CrI3 monolayer calculated by
Monto Carlo simulations including different magnetic pair
interactions, see also Fig. 1(a).
FIG. 1: Honeycomb lattice of CrI3 monolayer, with Cr (I) atoms
represented by blue (green) balls. Three magnetic pair interactions
are marked with J1, J2, and J3. (b) Edge-sharing CrI6 octahedra with
the local xyz coordinates. (c) Projected density of states for Cr 3d
and I 5p orbitals.
FIG. 4. Doping induced half
metallicity in CrI3 monolayer (a)
with 0.5 hole or 0.5 electron, and
(b) doping enhanced FM order.
The dashed vertical lines in (a)
refer to the shifting Fermi level.
Note that the itinerant hole
carriers in the broad valence
band are more efficient in
enhancing the FM stability than
the electron carriers in the
narrow conduction band.
Conclusions:
FIG.2: Schematic plot of FM superexchange interactions in CrI3
monolayer via the (x2− y2)-(px,py)-(x2− y2) orbitals (a) and (c), and
via the (x2− y2)-px-xy orbitals (b) and (c)
[1] M. A. McGuire et al. Chem. Mater. 27, 612 (2015)
[2] H. Wang et al. to be submitted.
(1) The FM order in the pure CrI3 monolayer is due to a superexchange
in the near 90◦ Cr-I-Cr bonds.
(2) A room temperature FM half metallicity could be achieved in CrI3
monolayer via a half hole doping.