I have an important question regarding minitest 2 question 2a. I believe there be a mistake (and if this is not the case then I hope to understand before tomorrow). When looking at tight-binding equation for phi1,n: I believe that the nearest neighbour hopping between between orbitals of different type (t_2) the nearest neighbours are phi2,n and phi2,n-1 as the left (different) neighbour is in the same unit cell. There is nothing stated that hopping can’t be in the same unit cell, as I believe it definetely can. Same for the thight-binding equation for phi2,n. Could you explain why my answer is wrong? I try to understand it before the exam tomorrow.
I also sent an email,
Thank you