QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: BandTheory on October 30, 2009, 19:44

Title: "Spatial Sizes," two probe systems and super cell vectors
Post by: BandTheory on October 30, 2009, 19:44

Hello,

Today I received the following error:

NLValueError: The resulting electrode cells for the electrodes have different spatial size in the A direction

So I'm guessing this has something to do with the super cell vectors.  A guess only.  Something about propagating the system about with the super cell vectors to do some Fourier business ?

I'm working with heterogeneous electrodes by the way, a (4,4) CNT on one side and a copper surface on the other.  If that were not the case I would just make both sets of super cell vectors the same, but since that is the case I am not sure how to change the vectors, assuming that is the issue.

Any help would be much appreciated,

BT

Title: Re: "Spatial Sizes," two probe systems and super cell vectors
Post by: Anders Blom on October 30, 2009, 21:53

The supercell vectors in the two directions perpendicular to the transport direction must be identical for left and right electrode, this is a fundamental assumption in these calculations.

However, in your system this is trivial to achieve; just make the proper unit cell to describe the Cu side, and then add enough vacuum to the CNT side to make it equal.