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We investigate the transport properties in nodal-line Weyl semimetal resonant tunneling junction. Double reflections and double transmissions appear, which are specular reflection, retroreflection, normal transmission, and specular transmission. The incident angle dependence transmissions and reflections are studied with different incident energies and different quantum well widths. The retroreflection and the specular transmission appear only when the incident angle of the electron θ is less than the critical value θc. As the incident energy approximately equals the z component of the momentum, double transmissions disappear completely, perfect retroreflection (specular reflection) can be found when θ is smaller (bigger) than θc. Under certain conditions, the transmission and reflection types and their magnitudes can be controlled. For the different cases that the nodal line of the Weyl semimetal is parallel to and perpendicular to the interface, the conductance spectra exhibit strong anisotropy. These physical phenomena help us to design nodal-line Weyl semimetal-based nanodevices.

Nanomechanics and real-time buckling deformation of an individual multi-walled carbon nanotube (MWCNT) were investigated through in situ nanoindentation within a transmission electron microscope (TEM). These in situ observations reveal a significant shell-to-Euler phase transformation in the buckling response of the nanotube. Objective evidences that the MWCNT possesses time-dependent characteristic were first suggested by combining in situ TEM nanoindentation performed strain rate influences on an individual MWCNT with classical molecular dynamics simulations. Structural evolutions and buckling instabilities for thin-wall and thick-wall CNTs are theoretically studied, indicating the role of the tube thickness and interwall van der Waals interactions in governing buckling behavior.

The conductance and the shot noise were investigated in graphene superlattice. A new Dirac point appears in the graphene superlattice and the position of the new Dirac point depends on the ratio of the width of the barriers to that of the wells. At the new Dirac point the conductance is minimum and the Fano factor reaches its max value 1/3. This Dirac point is robust against the magnetic field. In the energy window below the Dirac point, the magnetic field weakens the conductance but enhances the Fano factor.