Ferromagnetism/antiferromagnetism transition between semihydrogenated and fully-aminated single-wall carbon nanotubes

Abstract

We theoretically studied the ferromagnetism/antiferromagnetism (FM/AFM) transition between single-wall carbon nanotubes (SWCNTs) induced by chemical modifications of semihydrogenation (SH-) and full-amination (NH₂-). We found that armchairs with large diameters of SH-CNTs (n > 3) possess FM functions with intense magnetic moments, while armchair NH₂-CNTs (n = 4, 6, 8) are antiferromagnetic semiconductors. The FM/AFM transition is mainly dominated by different chemical modifications and sizes of SWCNTs whose distance between carbon atoms of unpaired electrons can regulate the intensity of p–p spin interactions. Moreover, the zigzag SH-CNTs and NH₂-CNTs are NM semiconductors. Thus, the electronic and magnetic properties of the SH- or NH₂-CNTs can be precisely modulated by controlling the hydrogenation or amination on the different types and diameters of CNTs, which provides a new and also simple process for magnetism optimization design in SWCNTs.