Role of the evanescent states in the elastic quantum transport

The role of evanescent states is always an issue in electronic transport, especially when the energy of the propagating electron is close to a band structure minimum. In this work, we investigate the effects of exact evanescent states on the calculation of the elastic quantum transport through a molecule connected by two quantum wires, based on the method presented in Ref.\,[1]. An exact treatment of evanescent (decaying) states involves the calculation of the complex band structure of the electrodes with imaginary parts of the k vectors. We have calculated the complex band structure under the plane-wave pseudopotential approach. The exact evanescent states are used in the transport calculations with auxiliary boundary condition as described in Ref.\,[1]. The results are exact numerical solutions of the scattering states under a plane-wave pseudopotential formalism. \newline \newline [1] L.W. Wang, Phys. Rev. B. {\bf 72}, 045417 (2005).