Antiferromagnetic topological insulators (AFM TIs), which host magnetically
gapped Dirac-cone surface states and exhibit many exotic physical phenomena,
have attracted great attention. The coupling between the top and bottom surface
states becomes significant and plays a crucial role in its low-energy physics,
as the thickness of an AFM TI film decreases. Here, we find that the coupled
surface states can be intertwined to give birth to a set of 2n brand new
Dirac cones, dubbed \emph{intertwined Dirac cones}, through the anisotropic
coupling due to the n-fold crystalline rotation symmetry Cnzβ (n=2,3,4,6) in the presence of an out-of-plane electric field. Interestingly, we
also find that the warping effect further drives the intertwined Dirac-cone
state into a quantum anomalous Hall phase with a high Chern number (C=n).
Then, we demonstrate the emergent six intertwined Dirac cones and the
corresponding Chern insulating phase with a high Chern number (C=3) in
MnBi2βTe4β/(Bi2βTe3β)mβ/MnBi2βTe4β heterostructures
through first-principles calculations. This work discovers a new intertwined
Dirac-cone state in AFM TI thin films and also reveals a new mechanism for
designing the quantum anomalous Hall state with a high Chern number.Comment: 7 pages, 4 figures+supplemental material