Quantum anomalous Hall effect by coupling heavy atomic layers with CrI3

Abstract

We explored the possibility of realizing quantum anomalous Hall effect by placing heavy-element atomic layer on top of monolayer CrI3 with a natural cleavage surface and broken time-reversal symmetry. We showed that CrI3/X (X = Bi, Sb, or As) systems can open up a sizable bulk gap to harbour quantum anomalous Hall effect, e.g., CrI3/Bi is a natural magnetic insulator with a bulk gap of 30 meV, which can be further enlarged via strain engineering or adjusting spin orientations. We also found that the ferromagnetic properties (magnetic anisotropic energy and Curie temperature) of pristine CrI3 can be further improved due to the presence of heavy atomic layers, and the spin orientation can be utilized as a useful knob to tune the band structure and Fermi level of CrI3/Bi system. The topological nature, together with the enhanced ferromagnetism, can unlock new potential applications for CrI3-based materials in spintronics and electronics.

New two-dimensional flat band materials: B3C11O6 and B3C15O6

“…The NFB is referred to as the singular NFB due to the discontinuity of wave functions at the degenerate points, 64,65 making it impossible to define a complete set of compact localized states for them. By introducing heavy atoms into the holes of the monolayer 66 or placing the 2D material on substrates containing heavy atoms, 67 the degeneracy of the energy bands can be lifted, resulting in the topologically nontrivial NFB with a nonzero Chern number, 45 which corresponds to the quantum anomalous Hall effect. The Stoner criterion 68 suggests that ferromagnetism can arise from DOS peaks with partial filling.…”

MX family: an efficient platform for topological spintronics based on Rashba and Zeeman-like spin splittings

“…In this sense, a subclass of two-dimensional materials with strong SOC is very promising for spintronics applications. Similarly, SOC when merge with other degrees of freedom such as valley and magnetism, reveal a spectrum of phenomena including non-magnetic, magnetic and light-controlled topological features [3][4][5][6][7]. The spintronics, which have been realized so far, are limited to the magnetic systems based on the exchange interaction of electrons with local magneticmoments to generate spin currents.…”

A generic dual d-band model for interlayer ferromagnetic coupling in a transition-metal doped MnBi2Te4 family of materials

“…Interestingly, the QAHE was first realized “extrinsically” in transition-metal (TM) doped three-dimensional (3D) TIs, but at a very low temperature. 5 Despite years of intensive efforts, 11–26 the observation temperature of the QAHE remains very low ranging from ∼30 mK (ref. 5) to ∼1 K. 27–29…”

“…Interestingly, the QAHE was first realized "extrinsically" in transition-metal (TM) doped three-dimensional (3D) TIs, but at a very low temperature. 5 Despite years of intensive efforts, [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] the observation temperature of the QAHE remains very low ranging from ∼30 mK (ref. 5) to ∼1 K. [27][28][29] Recently, a van der Waals (vdW) MnBi 2 Te 4 family of materials (MBTs) [30][31][32][33][34][35][36][37] have been discovered to provide an attractive material platform to explore the intrinsic QAHE.…”