Thermoelectric properties in twisted bilayer zigzag graphene nanoribbons

Abstract

In this study, we investigate the interplay of electron–electron interactions and zigzag edges geometry on the electronic properties of perfect and defective antiferromagnetic twisted bilayer graphene zigzag nanoribbons (TBLZGNRs), examining two distinct twist angles: ????1 = 3.48◦ and ????2 = 7.34◦. Both twist angles exhibit qualitatively similar behavior, while defects in the structure induce pronounced spin-polarization in the system. We examine the effects of applied transverse ???????? and vertical ???????? electric fields on the electronic and thermoelectric properties of TBLZGNRs (????1 = 7.34◦). In the perfect structure, transverse fields induce complete spin-polarization, while vertical fields exhibit weaker effects, generating only minor spin-polarization in the energy bands, charge current, and Seebeck effect. Defects introduce localized states near the Fermi energy. When external fields are applied, these defect-induced states lead to significant modifications in the band structure, including shifts in the bandgap and changes in the energy curvature. These modifications, induced by electric fields, twist angles, and structural defects in twisted bilayers, lead to complex spin-dependent transport and thermoelectric properties, profoundly influencing thermoelectric behavior control in such systems.