Bent zigzag graphene nanoribbons for spintronic applications

We investigate a spintronic device utilizing bent zigzag graphene nanoribbons (ZGNRs) to explore their spin-dependent electronic and transport properties. Employing a mean-field Hubbard model and the Landauer-B & uuml;ttiker formalism, we examine the effects of curvature on a large-scale bent ZGNR, revealing a spin-semiconducting phase in the antiferromagnetic ground state. The device comprises a circularly curved nanoribbon connected to two straight ZGNRs, forming a two-terminal, stretchable system. Our findings demonstrate that the spin energy gap and spin-splitting effects in bent ZGNRs are highly tunable via curvature parameters-total rotation, radius, and width. Even minimal curvature induces significant spin-dependent behavior and spin Seebeck coefficient (SSC), resulting in full spin polarization in both the density of states and the transmission coefficient. The degree of spin polarization increases with the bending parameter, leading to enhanced spin-polarized current and a substantial SSC. These results suggest that bent ZGNRs are promising for advancing spintronic applications, particularly in flexible device technologies.