Coupling Stacking Orders with Interlayer Magnetism in Bilayer H-VSe₂

【摘要】 Stacking-dependent magnetism in van der Waals materials has caught intense interests.Based on the first principle calculations,we investigate the coupling between stacking orders and interlayer magnetic orders in bilayer H-VSe₂.It is found that there are two stable stacking orders in bilayer H-VSe₂,named AB-stacking and A’B-stacking.Under standard DFT framework,the A’B-stacking prefers the interlayer AFM order and is semiconductive,whereas the AB-stacking prefers the FM order and is metallic.However,under the DFT+U framework both the stacking orders prefer the interlayer AFM order and are semiconductive.By detailedly analyzing this difference,we find that the interlayer magnetism originates from the competition between antiferromagnetic interlayer super-superexchange and ferromagnetic interlayer double exchange,in which both the interlayer Se-4p_z orbitals play a crucial role.In the DFT+U calculations,the double exchange is suppressed due to the opened bandgap,such that the interlayer magnetic orders are decoupled with the stacking orders.Based on this competition mechanism,we propose that a moderate hole doping can significantly enhance the interlayer double exchange,and can be used to switch the interlayer magnetic orders in bilayer VSe₂.This method is also applicable to a wide range of semiconductive van der Waals magnets.更多还原

【Abstract】 Stacking-dependent magnetism in van der Waals materials has caught intense interests.Based on the first principle calculations,we investigate the coupling between stacking orders and interlayer magnetic orders in bilayer H-VSe₂.It is found that there are two stable stacking orders in bilayer H-VSe₂,named AB-stacking and A’B-stacking.Under standard DFT framework,the A’B-stacking prefers the interlayer AFM order and is semiconductive,whereas the AB-stacking prefers the FM order and is metallic.However,under the DFT+U framework both the stacking orders prefer the interlayer AFM order and are semiconductive.By detailedly analyzing this difference,we find that the interlayer magnetism originates from the competition between antiferromagnetic interlayer super-superexchange and ferromagnetic interlayer double exchange,in which both the interlayer Se-4p_z orbitals play a crucial role.In the DFT+U calculations,the double exchange is suppressed due to the opened bandgap,such that the interlayer magnetic orders are decoupled with the stacking orders.Based on this competition mechanism,we propose that a moderate hole doping can significantly enhance the interlayer double exchange,and can be used to switch the interlayer magnetic orders in bilayer VSe₂.This method is also applicable to a wide range of semiconductive van der Waals magnets.更多还原