Topics

1

General Questions and Answers / Down spin conductance higher???

« on: February 5, 2013, 18:27 »

Hi

I am working with organic molecules, to calculate conductance with various transition metal doping. I used Vanadium for doping and got conductance values of 3.9e-5 S and ~2.8e-5 S for Up and Down spins respectively, at 0 Volt bias. However, when I changed the dopant to Cobalt, I got conductance values as 1e-5 and 2e-5 S. According to my understanding, most of the codes treat the electron spin with higher density as UP spin, and the other one as Down spin, so I would expect the decreasing conductance values for both cases, when comparing Up spin to down spin. So, my question is how ATK treats electronic spin? Is it sensible that I get more population of down spin than up spin?

Thanks

2

General Questions and Answers / Transmission pathways calculation from Transmission Spectrum?

« on: January 21, 2013, 18:36 »

Hi

I followed the mini tutorial to calculate transmission spectrum and I-V curve for a device (http://www.quantumwise.com/publications/tutorials/mini-tutorials/98-i-v-curve-and-voltage-drop). I was wondering if it is possible to calculate transmission pathways from the calculated transmission spectra. Since my devices are big, i break it into parts for different biases. Also, if I try to calculate transmission spectrum separately from the scf calculation or the calculated transmission spectra, what should the script look like for spin resolved case? Will I have to calculate for individual spin separately?

Thanks