Electronic Bands and Altermagnetic State Modulation in a Se-Rich In₂Se₄/Cr₂SeO Heterostructure

Abstract Two-dimensional van der Waals (vdW) heterostructures provide a versatile platform for engineering electronic properties through interfacial charge redistribution and orbital hybridization. In this work, a Se-rich-designated In₂Se₄/Cr₂SeO vdW heterostructure is proposed and investigated using density functional theory. The In₂Se₄ layer serves as an electronically active interface in which the enhanced selenium sublattice provides Se- p states capable of interacting with the Cr-3 d -derived states of an altermagnetic Cr₂SeO. A 1×1×1 In₂Se₄ monolayer and a strained (tensile in x and compressive in y) 1×2×1 Cr₂SeO cell were used to construct a supercell. The structural stability of the heterostructure is first evaluated through relaxation. The electronic properties are then characterized using spin-resolved band structures, projected density of states, orbital-resolved electronic states, and spatial charge density. The calculations reveal that interlayer coupling substantially modifies the electronic states near the Fermi level while retaining the characteristic spin-dependent structure of the Cr₂SeO layer. Overall, the heterostructure exhibits momentum-dependent semi-metallic/semiconducting behavior with strongly spin-selective local gaps. Se displacement in the In₂Se₄ monolayer acts as a symmetry and electrostatic control parameter that modifies the spin channels differently at different k-points. The resulting momentum-selective modification of Cr-derived states demonstrates the potential of Se-rich chalcogenide interfaces for tailoring the electronic structure of two-dimensional altermagnets. These findings suggest this heterostructure as a promising platform for investigating interfacial spin-dependent phenomena, provide insight into low-dimensional magnetic materials, and provide a theoretical foundation for nanoscale spintronic applications.