Conductance features and quasi-bound states in a longitudinal asymmetric quantum point contact

•The conductance in the asymmetric quasi-one-dimensional structure is studied.•We calculated resonances on all sheets of the Riemann surface of the Green function.•The correlation between conductance steps and Breit–Wigner resonances is found.

We calculate, in the Büttiker–Landauer approach, the ballistic conductance in the quasi-one-dimensional structure with longitudinal asymmetric potential. We have shown that there is a plateau of conductance in the area typical for the “0.7 anomaly”. Using the computational method proposed, we have calculated the energies and lifetimes of the electron resonance states in the system considered. It is shown that in this case the conductance plateau is generated by resonances of Breit–Wigner type.