Hi Bahareh,

That's quite simple: at the energy below -2t you have no propagating
modes in the wire and in the leads that you attach, and therefore
there's no conduction. So it's nothing really to fix, that is how your
system behaves.

Best,
Anton

On Wed, Aug 26, 2015 at 2:49 PM, Bahareh Goldozian
<bahareh.goldozian@teorfys.lu.se> wrote:
> Hello,
>
> I have tried to find the conductance for a three dimensional nanowire,
> I got some current for the zero energy however the current goes to zero when
> the energy is "-2t"
> How can I fix this problem?
>
> Thank you!
> Bahareh