I need to access to the number of atoms of my unit cell, the eigenvalue and eigenvectors for each eigenvalue of my Hamiltonian.
Is there any one to help me and let me know if it is possible in kwan to access them.
Could you post a short code example showing what you are doing? You refer to "atoms" and "unit cell", so I presume that you are trying to create a system with translational symmetry, and that each Kwant *site* corresponds to a single atom.
It is not 100% clear to me what you want when you say "the eigenvectors and eigenvalue" of your Hamiltonian; if your system has translational symmetry then presumably you want the eigen-decomposition *at a given quasi-momentum*, but you do not explicitly state this, so I am not sure.
Posting a complete code example is useful because it is more precise than describing your problem with words.