A clarification about IV characteristics

[medeepak]

Hi

i had formed a small AGNR with m=0, n=5 and z axis repetition 4 and calculated its current at 1.5 V bias and removed an atom from the center of the structure and calculated its current at 1.5V. I was hoping that current in the defectless structure would be high. But it turned out that current in structure in which an atom was missing was high (all other parameters were same and both structures were optimized using Brenner potential method). can anybody if this is correct or i am doing any mistake while forming the structures, please/ i have attached both the structures with this mail.

[nori]

But it turned out that current in structure in which an atom was missing was high

I guess it would be possible in your case because AGNR is a semi-conductor.
In ATK formalism, the electron transport between semiconductive electrodes is not ballistic but is derived from band-to-band tunneling and the central region play a role as a tunneling barrier.

Defects in central region effect the change of tunneling barrier's shape, and there is no guarantee that this change leads to the decrease of conductivity. 

[medeepak]

oh

i introduced a double defect and a stone walles defect as as well but in all cases the current in defective ones were higher than that in defect less ones (ratio varies like 1.5 to 2 for the three of them)