Tutorial "I-V curve and voltage drop" (problem: No voltage drop data in file)

[jiejiang]

Dear All,

I am learning tutorial "I-V curve and voltage drop".  I download the "resulting NetCDF file".  and download "lih2li_iv_analysis.py" from the tutorial. I then run the script lih2li_iv_analysis.py to calculate I-V curve and voltage drop. It  finishes and generates files, DeviceConfiguration (lih2li_iv_analysis.nc gID000),
TransmissionSpectrum (lih2li_iv_analysis.nc Transmission -0.0 V, ...), and GridValues (lih2li_iv_analysis.nc Voltage drop -0.1V,...).

I then download analyzer script, voltage_drop_analyzer.py, from the tutorial. I drop the script, voltage_drop_analyzer.py, and the file lih2li_iv_analysis.nc Voltage drop -0.1V to
to Custom Analyzer. I get the following error,
"No voltage drop data in file".

Could you please help me in this problem?

Thanks,

Jie

[Umberto Martinez]

That is because no ElectrostaticDifferencePotentials analysis are present in your lih2li_iv_analysis.nc file. See line 36/37 in  lih2li_iv_analysis.py which is commented out. The voltage drops are already stored in your  lih2li_iv_analysis.nc file. See the lines:

Code: python

    if float(bias)!=0.:  
        voltage_drop = potential - zero_bias_potential  
        nlsave(analysis_filename, voltage_drop, object_id="Voltage drop %s" % bias)  

You can analyze them directly with the 1D projector plugin instead of using Custom Analyzer (kind of outdated tool)