First principles study on stacking-dependent electronic structure of CrI3/α-In2Se3 heterostructures

The stacking orders that may be generated by mirroring a layer of CrX3 (X = I, Br, Cl) through its Cr atomic layer in heterostructures are easy to be ignored so that the influence of these stacking orders has not yet been well explored. In this paper, we have constructed all eight stable highly symmetric stacking orders that maintain translational symmetry in a CrI3/α-In2Se3 heterostructure and systematically studied the dependence of the structure, magnetism, electronic structure on stacking orders, and ferroelectric polarization directions by using the first principles method, especially that the system energy and magnetism have certain differences between normal and mirror stacking orders. The regulation of system energy and interlayer distance, magnetism, and band structure can be, respectively, explained by the different stacking relationships of atomic layers in different stacking orders, the different influences of different deformations of a CrI3 atomic structure on a magnetic exchange interaction in different stacking orders, and the different band alignments corresponding to different vacuum energy levels at different interfaces of α-In2Se3. Our work will have a certain reference value for understanding the material properties and practical applications of such ferromagnetic/ferroelectric heterostructures.