Hidden magnetism and split off flat bands in the insulator metal transition in VO2

Hidden magnetism and split off flat bands in the insulator metal transition in VO2

Blog Article

Abstract Transition metal d-electron oxides with an odd number of electrons per unit cell are expected to form metals with partially occupied energy bands, but exhibit in fact a range of behaviors, being either insulators, or metals, or having insulator-metal transitions.Traditional explanations involved predominantly electron-electron interactions in fixed structural symmetry.The present work focuses instead on the role of symmetry breaking local structural here motifs.

Viewing the previously observed V-V dimerization in VO2 as a continuous knob, reveals in density functional calculations the splitting of an isolated flat band from the broad conduction band.This leads past a critical percent dimerization to the formation of the insulating phase while lowering the total energy.In VO2 this transition is found to have a rather low energy barrier approaching the thermal energy at room temperature, suggesting energy-efficient switching in neuromorphic computing.

Interestingly, sufficient V-V dimerization suppresses magnetism, leading to the nonmagnetic insulating state, whereas magnetism appears when dimerization is reduced, forming a metallic state.This study opens the way to design novel functional quantum materials with wella color touch 77 45 symmetry breaking-induced flat bands.