QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: Hassan on January 13, 2015, 18:42

Title: Larger nanowire cross section shows smaller current
Post by: Hassan on January 13, 2015, 18:42

(http://i.imgur.com/AfwHIRh.png?1)

This is the Transmission spectrum curves of two different cross sections of nanowires. I am using ATK 13.8.1.

The larger cross section clearly has larger area under the curve, and just to make sure I integrated it and got the values of:

15.98 (for 8.65x5.76A) vs. 12.228 (for 5.76x5.76A). Both the Spectrums are generated using an applied voltage of 0.1V.

However, when I run TransObj.current() on the spectrum, Atomistix returns 29.5uA for the larger cross-section and 37.3uA for the smaller cross section. The parameters used in each simulation were the same (k-points, energy cutoff etc.)


What is going on here?

Thanks

Title: Re: Larger nanowire cross section shows smaller current
Post by: Anders Blom on January 13, 2015, 20:47

The current is not the area under the curve alone, you also need to account for the Fermi distributions of the two electrodes. The correct expression for the current can be found in the Reference Manual (http://quantumwise.com/documents/manuals/latest/ReferenceManual/index.html/ref.transmissionspectrum.html).