How to calculate the differential conductance?

[qingling]

Hello, everyone!
I ofen see  the differential conductance was calculated as a property of electron transport in many papers.  I search through the ATK manual and the forum, but do not know how to calculate it ? I now only know the method to calculate the conductance at zero bias.  I hope someone can give me a detailed input file.
Thank you very much!

[qingling]

Hope someone can give me a helpful suggestion!!!

[Anders Blom]

In principle it's very simple, right: compute the I-V curve and differentiate it. Of course, in practice it's not that simple because it's very hard to get so many points on the I-V curve that you get an accurate estimate of the numerical derivative.

In the new version of ATK ( 10.8 ) we have implemented a new function to get the differential conductance. You can read more about it at http://quantumwise.com/documents/manuals/latest/ReferenceManual/XHTML/ref.transmissionspectrum.html (scroll down to "Object methods").

[qingling]

Thank you for your help!!