Modulation of Electronic Properties of PtSe₂/XBr₂ (X = Ni, Co) Heterostructures by Strain and Electric Field

Integrating two-dimensional materials into van der Waals heterostructures (vdWHs) is widely acknowledged as an effective strategy for developing multifunctional devices. The electronic configuration and transport characteristics of PtSe₂/XBr₂ (X = Ni, Co) vdWHs are explored using the first-principles calculations. The most stable PtSe₂/NiBr₂(CoBr₂) heterostructures are identified through global search. The heterostructures are type II magnetic semiconductors with spin-up bandgap of 1.40(1.31) eV and spin-down bandgap of 0.89(1.16) eV. The total bandgaps are 0.88(1.12) eV. The bandgap of heterostructures can be manipulated by applying bidirectional strain within the range of 0 to 0.88 eV and 0 to 1.17 eV, respectively. External electric fields also have regulatory effects, within the range of 0.42 to 1.24 eV and 0 to 1.23 eV, respectively. During the modulation process, the magnetic properties of heterostructures also change. Finally, the band type can be modulated, enabling a transition from type I to type II, facilitating the semiconductor-metal transition. These research findings lay the groundwork for developing controllable and tunable two-dimensional magnetic semiconductor devices.