length as function of applied electric field.

[swap700]

I want to apply in plane electric to my system to observe piezoelectric response. I wanted to know, how can i make the length (positions) in the system, a function of the field,., ie how can i observe the piezoelectric response.

[zh]

The functionality for the calculation of piezoelectric response is not implemented. Please refer to other free codes such as Quantum-espresso and ABINIT.

[kstokbro]

In the current version of ATK you can add two metallic regions with opposite electro-static potential. In this way you will generate an uniform electric field between the metallic regions. However, this requires that you have vacuum in you cell, the metallic regions must be placed in the vacuum region.

[Anders Blom]

To clarify, ATK 11.2 and 11.8 do not have have a function for computing the piezoelectric effect in bulk periodic crystals. For that you need Berry phase calculations, which is on the list of planned features for a release in a not-to-distant future.

If you are interested in seeing how an applied electric field modifies e.g. the transport properties of a nanotube, or the band structure of a graphene sheet etc, then you can use the method described by kstrokbro, but it does require a reduced dimensionality of the system so you have place for the electrodes.