about Transmission pathway

[cinda]

I want to ask how do you calculate the pathway? Do you use a little bias voltage to know how does the current point? Because if there is no voltage, why do you know the current is from right to left or from left to right?
Thanks

[Nordland]

I think this paper is a quite good reference for it.
http://www.nature.com/nchem/journal/v2/n3/pdf/nchem.546.pdf

[cinda]

Thanks!