Hello,

I used the tutorial 2.5 for the circular graphene sheet, and in the example, an atom is deleted at sublattice a at (0,0) via

del sys [a(0,0)]

How can I replace this 'vacancy' with a different atom (with a different hopping parameter, say, 2)?

Also, from adding this new atom, do I adjust the hopping in sys using

sys[a(-2,1),b(2,2)] = -2 ?

Regards

James