Dear Adel: Thanks for your reply and the code. I think your code is basically the same as mine, except that I used only one lead and energy=0 to illustrate the problem. My issue is that the corresponding Green's function calculated by inverse is not equal to the one given by kwant. I indeed compared the selected sites, in your language, the surface Green's function.
I hope you can point out why the code of my last line give no zero matrix. Thank you very much. Bests, Wilson
