Messages

1

General Questions and Answers / IV for the doped system

« on: May 17, 2017, 13:04 »

Dear All,

I am trying to calculate the IV curve for a DOPED system. With the script below, the output gives me the results of a UN-DOPED system. For example, the transmission@0V_undoped is identical to the transmission@0V_doped. Should I add more codes to get the IV for a doped system?

Thanks for the help.

Note: /device/doping/device.nc is from the doped calculation.


path = u'/device/doping/device.nc'
configuration = nlread(path, object_id='gID000')[0]

# -------------------------------------------------------------
# IV Curve
# -------------------------------------------------------------
biases = [0.000000, 0.200000, 0.400000, 0.600000, 0.800000, 1.000000,
          1.200000, 1.400000, 1.600000, 1.800000, 2.000000]*Volt

iv_curve = IVCurve(
    configuration=configuration,
    biases=biases,
    energies=numpy.linspace(-2,2,101)*eV,
    self_energy_calculator=RecursionSelfEnergy(),
    energy_zero_parameter=AverageFermiLevel,
    infinitesimal=1e-06*eV,
    selfconsistent_configurations_filename_prefix="ivcurve_selfconsistent_configuration_",
    log_filename_prefix="ivcurve_"
    )
nlsave('analysis.nc', iv_curve)
nlprint(iv_curve)

2

General Questions and Answers / Re: gating_molecularjunction_transmission

« on: December 5, 2016, 12:17 »

Hi,

Attached is the script I calculated the transmission (let's label it trans_A). Then I do the gating looping over numpy.linspace(-2.0, 1.0, 10)*Volt. (Let's label the transmission at 0 gating voltage as trans_B)

The trans_A and trans_B is different.  Any idea? Thanks,

3

General Questions and Answers / gating_molecularjunction_transmission

« on: December 5, 2016, 10:42 »

Hi,

I have two zero-bias electronic transmissions of a molecular system(DFT+NEGF approach). One  is calculated from the standard way. The other is calculated from a gating loop at 0 gating voltage[the gating script below].

My question: Isn't that the two transmissions should be the same? But I got two different transmissions. Any idea?


Regards,
Chengjun



  1 # Read in the old configuration
  2 device_configuration = nlread("/analysis.nc",DeviceConfiguration)[0]
  3 calculator = device_configuration.calculator()
  4 metallic_region0 = device_configuration.metallicRegions()[0]
  5
  6 # test keywords: metallicaRigions
  7
  8
  9 # Define gate_voltages
 10 gate_voltage_list=numpy.linspace(-2.0, 1.0, 10)*Volt
 11 for gate_voltage in gate_voltage_list:
 12     # set the gate potential
 13     device_configuration.setMetallicRegions(
 14         [metallic_region0(value = gate_voltage)] )
 15
 16     # make a copy of the calculator and attach it to the configuration
 17     # restart from the previous scf state
 18     device_configuration.setCalculator(calculator(),
 19         initial_state=device_configuration)
 20
 21     #Analysis
 22     filename= 'gate_vdp.nc'
 23     electron_density = ElectronDifferenceDensity(device_configuration)
 24     nlsave(filename, electron_density,object_id='dens'+str(gate_voltage))
 25
 26     electrostatic_potential = ElectrostaticDifferencePotential(device_configuration)
 27     nlsave(filename, electrostatic_potential, object_id='pot'+str(gate_voltage))
 28
 29     transmission_spectrum = TransmissionSpectrum(
 30         configuration=device_configuration,
 31         energies=numpy.linspace(-2,2,200)*eV,
 32         )
 33     nlsave(filename, transmission_spectrum,object_id='trans'+str(gate_voltage))
 34     nlprint(transmission_spectrum)

4

General Questions and Answers / possibility to decompose the phonon transmission into different modes?

« on: April 21, 2016, 22:14 »

Hi all,

Regarding the phonon transport in ATK(the Green function approach), is it possible to decompose the phonon transmission function by different polarisations, e.g. longitudinal, transverse, flexural modes?

Regards,
Chengjun