Enhancing spin splitting by symmetry and molecular orbital hybridization in VO2.

[Display omitted] • VO 2 has a non-relativistic splitting of 8.2 meV and its spins are polarized along the (2 1 0) direction. • The splitting is affected by the interfacial materials and the interfacial types. • In VO 2 /TiO 2 composite layer, the splitting of VO 2 increases to 164 meV (245 meV) induced by dual interfaces (interface and surface). In spintronic devices, one of the concerned focuses is spin splitting, which is existing in heavy metal with strong spin–orbit coupling (SOC) and some materials with broken symmetry. Recently, non-relativistic spin splitting originated from symmetric breaking has been proved in materials with low atomic numbers. Herein, based on inherent asymmetric octahedrons in vanadium dioxide (VO 2) and the adjustable charge-spin conversion efficiency, we mainly survey non-relativistic spin splitting in VO 2 from a symmetric perspective of bulk, interface, and surface, and hybridization of the molecular orbital. The results demonstrate that there is a tiny spin splitting (8.2 meV) in the rutile-like monoclinic (RM) VO 2 bulk. Nevertheless, a huge splitting can be realized by modulating the hybridization of molecular orbital by fabricating the interface with different materials. Moreover, when we give priority to VO 2 (RM)/TiO 2 composite layer (164 meV), the results suggest that the splitting can be also manipulated by different interfacial types and increased the number of layers of VO 2 (RM). This manner of manipulating symmetries of interface and surface and changing the hybridization of molecular orbital sheds light on understanding the electronic structure and acquiring an enhanced splitting of VO 2 , which provides the possibility of the application of VO 2 in spintronic devices. [ABSTRACT FROM AUTHOR]