Structural Asymmetry-Facilitated Tunability of Spin Distribution in the (10,0) Carbon Nanotube Induced by Charging

Constructing the asymmetric electronic structure of low-dimensional carbon nanomaterials is significant for application of molecular devices, such as magnetic switches. In this work, we use density functional theory to investigate the asymmetric spin distribution in a typical (10, 0) carbon nanotube by capping one end with a fullerene hemisphere and saturating the dangling bonds with hydrogen atoms at the other end. Calculated results indicate that this geometry obviously modified the distribution of spin density along the tube axis, and the electrons present were antiferromagnetically coupled at both ends. Specifically, the change in magnetic order at the end of the cap can be changed with either the increase or decrease of the charge. In addition, the analysis of electron density difference shows that charge induces gain or loss of electrons not only at the open end, but also at the cap end. These findings provide a strategy for controlling spin distribution for nanoscale functional molecular devices through a simple charge adjustment.