A controllable spin flip and filter in zigzag graphene nanoribbons with triangular defect

Based on the recursive Green-function method together with Landauer-Buttiker formalism, we theoretically study the controllable spin-dependent electron transport properties by using zigzag graphene nanoribbons (ZGNRs) with triangular nanoconstrictions in the presence of the ferromagnetic strips and spatial modulation of Rashba spin-orbit coupling (RSOC). In this structure, the peaks of spin-flip and spin-conserved conductance can be modulated by the strength of RSOC and exchange magnetic field. The distribution of the local density of states (LDOS) around triangular nanoconstrictions is predicted. The spin filtering effect of ZGNRs with triangular and rectangular nanoconstrictions are compared by spin conductance from left (L) to right (R) lead and R to L lead, respectively. The results might be useful in designing a bidirectional spin converter and spin filter with the modulation of the multi-parameter.

Automated summary

Based on the Green-function method and Landauer-Buttiker formalism, this study investigates the spin-dependent electron transport properties of zigzag graphene nanoribbons (ZGNRs) with triangular nanoconstrictions in the presence of ferromagnetic strips and spatial modulation of Rashba spin-orbit coupling (RSOC). The controllability of spin-flip and spin-conserved conductance peaks is demonstrated by adjusting RSOC strength and exchange magnetic field. The local density of states (LDOS) distribution around triangular nanoconstrictions is predicted. The spin filtering effect of ZGNRs with triangular and rectangular nanoconstrictions is compared.