Structure and magnetic properties of open-ended silicon carbide nanotubes

Nanotubes with open ends have been found to offer interesting opportunities in many applications. In this paper, the structures and magnetic properties of a series of open-ended SiCNTs have been studied through first-principles simulation. Our results reveal that the structures and magnetic properties of the open-ended SiCNT are strongly dependent on the tube diameter and chirality: (i) the open-ended armchair SiCNT is nonmagnetic due to the formation of spin-antiparallel pairs between the Si and C atoms at the tube mouth, and the self-closure behavior occurs at the tube mouth; (ii) the magnetic moment of the C-rich-ended zigzag or chiral SiCNT is nearly equal to the number of dangling bonds on the tube mouth; (iii) for the Si-rich-ended zigzag or chiral SiCNT, the spin density mainly locates on the isolated Si atoms at the tube mouth, the magnetic moment of each Si atom at the tube mouth is strongly dependent on the tube diameters. Our results might be helpful in deeply understanding the magnetic properties of SiCNTs, as well as provide guidance to design novel SiCNT-based nanodevices such as spintronic or field-emission display devices.