Hi experts,

 

I am brginner in kwant trying to investigate a graphene ribbon with onsite Coulomb energy U<n>, where the electron density <n> at each site should be determined self-consistently.  I used the "shape" method to generate sites and to set the oniste energy -  such as sys[lat.shape(circle, (0, 0))]=onsite. I could obtain <n> of1-D array whose index correponds to the orbital number by using kwant.wave_function. Then, I have to put U<n> as onsite energy. But, I have a problem that, in kwant, the onsite energy should be set as a number or a 2x2 tiny-array. Is there any way to set the onsite Coulomb energy?

 

Any advice will be greatly appreciated,

Lee