Superior electronic structure of two-dimensional 3d transition metal dicarbides for applications in spintronics

Abstract

The past decade has been particularly creative for spintronics since the discovery of various two-dimensional (2D) materials. However, their applications in spintronics have been limited due to the lack of intrinsic magnetism. Herein, we predict a new type of 2D transition metal dicarbides with great potential in spintronics due to the itinerant magnetism of the d orbital. It was observed that in ScC₂, TiC₂, CuC₂ and ZnC₂, no magnetism was observed. VC₂, MnC₂ and NiC₂ are magnetic metals, and FeC₂ and CoC₂ are spin-polarized magnetic semiconductors. Interestingly, CrC₂ is half-metallic. The large gap opening of about 15 meV in CrC₂ induced by SOC is related to the p–d hybridization between the C₂ dimer and Cr. The chiral edge states and Chern number results suggest that the SOC gap is topologically trivial. The uniaxial compressive strain along the y-axis can induce a transition from half-metal to magnetic semiconductor, spin gapless semiconductor and metal in monolayer CrC₂. A CrC₂-based field-effect transistor on a flexible substrate is proposed with the aim of realizing electrical control on the SOC-induced insulating state and on the carriers’ spin orientation. Our findings provide a new scheme for future multifunctional 2D nanoelectronics and spintronics devices.