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Messages - Gaurav

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1
Dear All,

Is it possible to comment on the structural and thermodynamic stability of a two-probe model?

Thank you.
Gaurav

2
Dear Kenta,

Please refer to our publications on SET for switching and sensor application, for a basic understanding of the device mechanism.
https://doi.org/10.1109/TNANO.2019.2945995
http://dx.doi.org/10.1007/s11664-020-08663-0
http://dx.doi.org/10.1049/PBCS049E_ch3
Hope you find these helful.
Also, you can't have IV characteristics for the SET in ATK; however, you can plot charge vs. voltage (either Vds or Vg) for the same by running a python script.

Good luck!

3
Dear all,

Various approaches have been utilized to break the spin degeneracy in ZGNRs, one of them is by applying an external electric field.
I want to design a 2-probe model, where we can have half-metallic electrodes via. electric field. I have attached a sample device model for your reference. Is it the right way to design??

Thank you so much!

4
Thank You Dr. Mlee.

5
Dear all,

I have a query related to relaxing the device central region as mentioned in the following tutorial:
 https://docs.quantumatk.com/tutorials/fe_mgo_fe/fe_mgo_fe.html#femgofe-relax 

How can be we perform  optimization of similar system (mainly 2-probe model for PC/APC spin transport) if we have modified the left/right electode via substitutional doping or adsorbtion to induce magnetism?? As implying constraint type to rigid/fixed to electrode extensions will prevent necessary changes at substitution or adsorption site.

Thank you in advance.

6
Thank you, Dr. Troels.
In various literature, the Perdew–Burke–Ernzerhof (PBE) form has been used to study spin polarized systems.

7
Dear All,

Which electron exchange and correlation functional is better suited with the  SGGA calculation for spin transport in 1D material?
Is it PBE or RPBE functional?

Thanks in advance.

8
Dear all,

I am trying to study the impact of substitutional doping in buckled silicene armchair nanoribbon in Quantum ATK 2019.3 version and followed the tutorial entitled 'Spin-orbit splitting of semiconductor band structures " for Si as a reference.
https://docs.quantumatk.com/tutorials/spin_orbit_bandstructures/spin_orbit_bandstructures.html#dyu1989spin

 I have taken exchange correlation functional to “SMGGA" along with OMX pseudopotentials. But, i am not getting a splited VB maximum band. Kindly help me out.

9
Script used for calculation is mentioned below

read Total Energy script.
---

from NL.IO.NLSaveUtilities import nlinspect
from NanoLanguage import *

#define function for reading in total energy and gate voltage data from a file
def readTotalEnergy(filename):
    """
    function for reading a list of total energies and gate voltages from a file
        @param filename : filename of the netcdf file
        @return voltages, energies : list of gate voltages and energies
                                    found in filename
    """
    if filename == None:
        return
    #get list of data in file
    file_data = nlinspect(filename)
    if file_data == None:
        raise ValueError, "Wrong file format"
       
    total_energy_list = numpy.array([])
    gate_voltage_list = numpy.array([])
       
    for id in file_data:
        if (id[0] == 'TotalEnergy'):
            total_energy=nlread(filename, object_id = id[1])[0]
            total_energy_list = numpy.append(total_energy_list,
                                            total_energy.evaluate().inUnitsOf(eV))
            #extract the gate voltage from the id of the data
        if id[1][0:3] == 'gID':
            gate_voltage = 0.0
        else:
            gate_voltage = float(id[1].strip(
                            "abcdefghijklmnopqrstuvxyzABCDEFGHIJKLMNOPQRSTUVXYZ"))
        gate_voltage_list = numpy.append(gate_voltage_list,gate_voltage)
       
    if len(total_energy_list) ==0:
        raise ValueError, "No total energy in NC file"
    #sort the data
    index_list = numpy.argsort(gate_voltage_list)
    return gate_voltage_list[index_list], total_energy_list[index_list]

------------


Total Energy VS gate voltage script


-------

from readTotalEnergy import readTotalEnergy

# define the work function of gold
w = 5.28

#read in the total energy data from the files: pentacene_set[-2,-1,0,1,2].nc
voltage_list= []
energy_list = []

#loop over the charge states
charge_states = [-2,-1,0,1,2]
for q in charge_states:
    voltage,energy = readTotalEnergy('pentacene_set'+str(q)+'.nc')
    voltage_list = voltage_list + [voltage]
    # add energy of additional/missing electrons on benzene
    energy = energy -q*w
    energy_list = energy_list + [energy]
   
#plot the total energies
import pylab
pylab.figure()
for i in range(len(voltage_list)):
    pylab.plot(voltage_list,energy_list)
   
pylab.xlabel("Gate voltage (Volt)")
pylab.ylabel("Total Energy (eV)")
pylab.show()

---

I was facing problem in attaching script file that's why copying script in reply tab.

Thanking you!

10
Dear Sir/Madam,

I am attaching .log file for both functional block of python script.

11
Good Morning to all,

I am using ATK-VNL version 2016.0 for Single_electron transistor based on different molecule as per Benzene Single-Electron Transistor Tutorial Version 2015.2.
Till Gate voltage scan,I havn't got any error.But,For read total energy and total Vs gate voltage earlier i got intended block error for python script but i sorted it out by proper
Tab positioning.
Now,For total energy Vs gate voltage script iam getting following error:

C:\Users\HPi7007\Desktop\Pentacene_SET\readTotalEnergy.py:16: FutureWarning: comparison to `None` will result in an elementwise object comparison in the future.
  if file_data == None:
Traceback (most recent call last):
  File "TEvsVg.py", line 13, in <module>
    voltage,energy = readTotalEnergy('pentacene_set'+str(q)+'.nc')
  File "C:\Users\HPi7007\Desktop\Pentacene_SET\readTotalEnergy.py", line 39, in readTotalEnergy
    return gate_voltage_list[index_list], total_energy_list[index_list]
IndexError: index 2 is out of bounds for axis 1 with size 2

I am attaching .py file for both script.

Thanking you!

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