Joseph Weston <joseph.weston08 <at> gmail.com> writes: > > If I have understood correctly you have essentially rotated the lattice > by a right angle. If this is the case, and if you have attached > leads on the left and right as you say then you are no longer simulating > the same system as before, surely? Before, the horizontal edges were > zigzag and now they are armchair. > > As I understand it the transport properties of graphene nanoribbons with > armchair or zigzag edges are fundamentally different, so will > this not affect any quantities calculated?
Joseph, of course you are quite correct. In my reply I denoted the expanded unit cell by \_/ simply because it would fit on one line whereas the other orientation \ | / would not. You are absolutely right about the changes in transport if the leads are attached on the zigzag edges instead of the armchair ones. And thank you Michael for posting the example using add_site_family(). That is most helpful. All the best. David