Strain-tunable half-metallicity in ${\mathrm{VSe}}_2/{\mathrm{Sc}}_2{\mathrm{CO}}_2$ van der Waals heterostructures

The quest for advancing the development of next-generation nanospintronic devices has propelled extensive research into the realization and control of half-metallicity in 2D materials. Here, the multiferroic ${\mathrm{VSe}}_2/{\mathrm{Sc}}_2{\mathrm{CO}}_2$ vdW heterostructures are theoretically investigated by using density functional theory to search for half-metallicity. Our theoretical exploration reveals that the ${\mathrm{VSe}}_2$ layer showcases a unique capability to transit between semiconducting and half-metallic behavior by precisely manipulating the ferroelectric polarization states of the ${\mathrm{Sc}}_2{\mathrm{CO}}_2$ layer. We further delve into the diverse electronic properties of the ${\mathrm{VSe}}_2$ layer within the heterostructure, employing uniaxial tensile strain engineering to investigate its behavior in both the semiconductor and half-metallic states. In the semiconductor state, this electronic property of the ${\mathrm{VSe}}_2$ layer remains unchanged with strain. In contrast, in the half-metallic state, the ${\mathrm{VSe}}_2$ layer undergoes a fascinating modulation, transiting from the spin-down half-metal to the metal and then to the spin-up half-metal as the strain increases from $0\%$ to $6\%$. This intriguing phenomenon is elucidated by the intricate rearrangement of the inner V atomic orbitals in response to strain.