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zerothi / sisl

Electronic structure Python package for post analysis and large scale tight-binding DFT/NEGF calculations
https://zerothi.github.io/sisl
Mozilla Public License 2.0
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I-V curve with tbtrans #820

Closed masume70 closed 2 weeks ago

masume70 commented 2 weeks ago

Hello,

I have a question about obtaining an I-V curve using TBtrans. Is it possible to get the I-V curve without performing transiesta calculations and using only TBtrans? As far as I know, we can read the I-V curve from the output of TBtrans. So, is it possible to obtain it using just sisl and TBtrans without transiesta? Thanks, Masoumeh

zerothi commented 2 weeks ago

Yes and no.

Generally an applied bias will change the electronic structure, due to charge renormalizations, and fields etc.

Hence, one cannot do I-V curves from models calculated at 0 V.

Yet, TBtrans does allow one to do I-V curves, even if the electronic structure is not self-consistently solved with the applied bias. If you do, I would recommend you to add something like

%block TBT.Elec.<name>
  V-fraction 1
%endblock

to your electrode blocks. This will simulate a potential shift in the device coupling region between the electrodes and the device. This will not do anything if you have an orthogonal basis.

So, my recommendation is no.

zerothi commented 2 weeks ago

Sorry. That can be very difficult, and I simply don't have the time to answer all requests that comes by like this. It depends on a lot of things.... So ain't easy to answer generically.

masume70 commented 2 weeks ago

Thanks