I give the examples of voltage drop calculated with ATK-SE 2010.02 in this thread.
As you know, how to calculate Hartree potential is changed in new ATK (since 2009.06),
where Hartree potential is calculated against only central region, while in ATK 2008.10 it is calculated against whole system(left electrode + central region + right electrode).
This change bring mainly two benefits as follows:
1. New method makes SCF convergence more stable,
2. more reliable voltage drop can be obtained.
"more reliable" means that voltage drop mainly occurs around high resistance region like molecule, insulator, interface, and so-on, and is smoothly connected to reservoirs.