QuantumATK Forum
QuantumATK => General Questions and Answers => Topic started by: karma on January 9, 2018, 20:21
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how do we test the convergence for photocurrent calculation.
also is the bias volatge applied to the left and right electrodes in the device calculator setting applicable during photocurrent analysis
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Dear all,
1. How to calculate current density as a function of bias voltage more easily? [PHYS. REV. APPLIED 10, 014026 (2018)]
2. How to calculate the transmission as a function of energy for the given photon? [Nano Letters 2018 18 (11), 7275-7281 ]
Thank you very much for your help.
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Convergence checks should be performed for the usual DFT settings.
When a good DFT simulation has been performed the kpoints and energies/energy_resolution used in the Photocurrent calculation should be checked.
A bias voltage is included in the usual way through the device calculator. Then one perform the calculation of the Photocurrent for each separate and converged device configuration at a given bias voltage.
The Photocurrent object has a query function "photocurrent.photonMediatedTransmission(photon_mode,...)" that can be used to obtain the transmissions as a function of energy for a selected photon energy index "photon_mode".
Please see the reference manual entry for Photocurrent for full description of the inputs to this query function:
https://docs.quantumwise.com/manual/Types/Photocurrent/Photocurrent.html#photocurrent-c
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Convergence checks should be performed for the usual DFT settings.
When a good DFT simulation has been performed the kpoints and energies/energy_resolution used in the Photocurrent calculation should be checked.
A bias voltage is included in the usual way through the device calculator. Then one perform the calculation of the Photocurrent for each separate and converged device configuration at a given bias voltage.
The Photocurrent object has a query function "photocurrent.photonMediatedTransmission(photon_mode,...)" that can be used to obtain the transmissions as a function of energy for a selected photon energy index "photon_mode".
Please see the reference manual entry for Photocurrent for full description of the inputs to this query function:
https://docs.quantumwise.com/manual/Types/Photocurrent/Photocurrent.html#photocurrent-c
Dear Tue Gunst,
I also want to obtain the photon mediated transmission like that in Figure 6c of your paper [Nano Letters 2018 18 (11), 7275-7281]. However, when I use the following script in the .py input file, nothing obtianed except the photocurrent. Can you kindly give some help? thanks!
===
# -------------------------------------------------------------
# Analysis from File
# -------------------------------------------------------------
device_configuration = nlread('Au-Ben-Au-0.0.hdf5')[1]
# -------------------------------------------------------------
# Photocurrent
# -------------------------------------------------------------
kpoints = MonkhorstPackGrid()
photocurrent = Photocurrent(
configuration=device_configuration,
energies=numpy.linspace(-2, 2, 101)*eV,
photon_energies=numpy.linspace(0, 5, 10)*eV,
kpoints=kpoints,
photon_polarization=[0+0j, 0+0j, 1+0j],
energy_resolution=0.05*eV,
calculate_all_transmissions=True,
)
nlsave('Au-Ben-Au-0.0-PC.hdf5', photocurrent)
photocurrent.photonMediatedTransmission(photon_mode=0)
===
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The photon mediated transmission is not plotted in the gui but you can obtain the data from the object as you are suggesting.
energies = photocurrent.energies().inUnitsOf(eV)
transmission = photocurrent.photonMediatedTransmission(photon_mode=0)
and then plot these two variables with pylab or other prefered plotting tools (select wanted photon_mode index for which you want to plot the transmission).
Please see the object description here for further details:
https://docs.quantumatk.com/manual/Types/Photocurrent/Photocurrent.html#NL.Analysis.Photocurrent.Photocurrent
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The photon mediated transmission is not plotted in the gui but you can obtain the data from the object as you are suggesting.
energies = photocurrent.energies().inUnitsOf(eV)
transmission = photocurrent.photonMediatedTransmission(photon_mode=0)
and then plot these two variables with pylab or other prefered plotting tools (select wanted photon_mode index for which you want to plot the transmission).
Please see the object description here for further details:
https://docs.quantumatk.com/manual/Types/Photocurrent/Photocurrent.html#NL.Analysis.Photocurrent.Photocurrent
Dear Tue Gunst,
I now can get the photon mediated transmission.
Thanks very much for your kind reply.
With best regards,
/Guang-Ping Zhang