Tunable Spin Polarization of Zigzag–Zigzag Heterojunction Carbon Nanotubes

Abstract

Adjusting the spin polarization of carbon nanotubes is critical for achieving functional applications of spintronic devices such as magnetic switches. Herein, heterojunction carbon nanotubes (HCNTs) are constructed by connecting two different zigzag edges to achieve this goal. First‐principles calculations indicate spin ferromagnetic (FM) or antiferromagnetic (AFM) coupling in the corresponding structure, which can be regulated by the number of carbon atoms at the zigzag edges of the HCNTs. Further calculations related to the charged HCNTs indicate that electronic ground states of the same structure can be transformed from spin AFM to spin FM coupling states. Thus, the behavior of spin polarization for zigzag–zigzag HCNTs can also be regulated by the charge. This finding opens up a new approach for spin adjustment, which can potentially contribute to the design of spintronic devices.