How to build two probe system based on graphene ribbon of deformation ?

[benhuzhou]

Hello, everyone!
I want to anwser a question about graphene ribbons,  I expect to build two probe system based on graphene ribbons of deformation. More specially, if I know the change of  the C-C bonds and C-C angles, when I drag the graphene script into molecular builder or atomic manipulator, I can not chang the C-C length and C-C angles. Can someone offer some script for this?
Thank you very much!

[Anders Blom]

Are the deformations uniform, i.e. corresponding to a stretch of the ribbon in some direction, or local, i.e. different for different sites? If the former is the case, we can probably quite easily figure out how to stretch the unit cell. If the latter, I think you have to do it by hand...

[benhuzhou]

Dear Anders Blom:
    Thank you very much for your answer!
  On the one hand, I want to build two probe system based on graphene ribbon of deformations uniform. Just as your said,  the deformations can be considered to a stretch of the ribbon in some direction. For example, if I strech the zigzag  (armchair) ribbon along the zigzag direction or armchair direction, there are two kinds of C-C bond which the changed length will be different, and the corresponding C-C bond angles also be changed. How to obtain the script?
  On the other hand, if the deformatioms are not uniform. Howerer, the deformations are uniform along zigzag or armchair direction. For example, if I stretch the central ribbon along Z direction, the C-C bonds of changed length become  larger and larger from central region of the ribbon to edges. How to write the scipt and connect the two electrodes (I think the electrode also need to chang in order to connect the deformations of central ribbos)?     
    Thanks again, Anders Blom. My English is poor, I think whether you can understand the meaning of above or not.

[Anders Blom]

One way to do this would be to build perfect "building blocks" (without strain) and then bring them into the Bulk Builder. If you keep the fractional coordinates fixed, but change the unit cell, then you obtains a stretched structure! Then just just put the pieces back together again (electrode + central region).

This is quite easy to do as long as the deformation is parallel or perpendicular to the transport directions. Well, anyway, you can always decompose a general deformation in two components, as long as it's a simple strain (or even some version of hydrostatic pressure) and not a "shear" stress.

[benhuzhou]

Dear Anders Blom:
    Thank you very much! I will try.