Valley and subband-selective electronic transport through a line defect embedded carbon nanotube.

We theoretically demonstrate the possibility of realizing the valley and subband-selective electronic transport properties if line defects are embedded in an armchair carbon nanotube. The physical mechanism for such an interesting transport property is clearly due to the appearance of the special subband spanning two valleys without dispersion, caused by the presence of the line defect. In contrast to a perfect zigzag-edged graphene nanoribbon, which was previously suggested to be a nanodevice prototype to manipulate the valley and subband degrees of freedom, our structure, the line defect embedded carbon nanotube, is less demanding for the current nanotechnique. Therefore, our theoretical investigation provides an alternative and feasible structure to design carbon-based nanoelectronic devices.

A novel self-consistent-field lattice model for block copolymers.

We develop a self-consistent-field lattice model for block copolymers and propose a novel and general method to solve the self-consistent-field equations. The approach involves describing the polymer chains in a lattice and employing a two-stage relaxation procedure to evolve a system as rapidly as possible to a free-energy minimum. In order to test the validity of this approach, we use the method to study the microphases of rod-coil diblock copolymers. In addition to the lamellar and cylindrical morphologies, micellar, perforated lamellar, gyroid, and zigzag structures have been identified without any prior assumption of the microphase symmetry. Furthermore, this approach can also give the possible orientation of the rods in different structures.