Author Topic: Question about Modeling metal–semiconductor contacts: The Ag–Si interface  (Read 6837 times)

0 Members and 1 Guest are viewing this topic.

Offline 395235863

  • Heavy QuantumATK user
  • ***
  • Posts: 81
  • Country: cn
  • Reputation: 0
    • View Profile
what the meaning of r_pot in http://docs.quantumwise.com/_downloads/pldos_hdp.py

Thank you very much !

Offline Daniele Stradi

  • Supreme QuantumATK Wizard
  • *****
  • Posts: 286
  • Country: dk
  • Reputation: 3
    • View Profile
Hello,

r_pot gives the value of the averaged potential at the rightmost side of the interface, e.g., at Z = 400,200,80 Ang of Fig.6 in PRB 93 155302 (2016).

In fact, few lines later in the script you can see that the Schottky barrier at the interface is evaluated as:
schottky = max(av_pot-r_pot)

Regards,
Daniele.

Offline 395235863

  • Heavy QuantumATK user
  • ***
  • Posts: 81
  • Country: cn
  • Reputation: 0
    • View Profile
Hello,

r_pot gives the value of the averaged potential at the rightmost side of the interface, e.g., at Z = 400,200,80 Ang of Fig.6 in PRB 93 155302 (2016).

In fact, few lines later in the script you can see that the Schottky barrier at the interface is evaluated as:
schottky = max(av_pot-r_pot)

Regards,
Daniele.
Thank you very much!
What the difference betweet r_pot and CBmin(The conduction band minimum in the right electrode)?

Offline Daniele Stradi

  • Supreme QuantumATK Wizard
  • *****
  • Posts: 286
  • Country: dk
  • Reputation: 3
    • View Profile
r_pot is the value of the potential obtained from the HartreeDifferencePotential whereas CBmin is the value of the conduction band minimum obtained from the DeviceDensityOfStates.

Ideally the two should match, but in practice there is always some small uncertainty, since one has to decide the threshold under which the DDOS is equal to zero. In the script the threshold is set to 0.01 eV^-1:

# Threshold under which the DOS is considered zero (Band gap region)
thr = 0.01


Regards,
Daniele.

Offline 395235863

  • Heavy QuantumATK user
  • ***
  • Posts: 81
  • Country: cn
  • Reputation: 0
    • View Profile
r_pot is the value of the potential obtained from the HartreeDifferencePotential whereas CBmin is the value of the conduction band minimum obtained from the DeviceDensityOfStates.

Ideally the two should match, but in practice there is always some small uncertainty, since one has to decide the threshold under which the DDOS is equal to zero. In the script the threshold is set to 0.01 eV^-1:

# Threshold under which the DOS is considered zero (Band gap region)
thr = 0.01


Regards,
Daniele.

Is HartreeDifferencePotential in ATK 2016 the same to ElectrostaticDifferencePotential in ATK 2015?

Offline Daniele Stradi

  • Supreme QuantumATK Wizard
  • *****
  • Posts: 286
  • Country: dk
  • Reputation: 3
    • View Profile

Offline 395235863

  • Heavy QuantumATK user
  • ***
  • Posts: 81
  • Country: cn
  • Reputation: 0
    • View Profile
Case Studies » Modeling metal–semiconductor contacts: The Ag–Si interface
http://docs.quantumwise.com/casestudies/ag_si_interface/ag_si_interface.html

In Projected local density of states part, it mentioned that
Quote
Moreover, the averaged potential nicely follows the conduction band minimum, both at the interface and far from it.

My question is how draw the line of valence band max maximum along the C direction ?

Thank you very much!

Offline 395235863

  • Heavy QuantumATK user
  • ***
  • Posts: 81
  • Country: cn
  • Reputation: 0
    • View Profile
Case Studies » Modeling metal–semiconductor contacts: The Ag–Si interface
http://docs.quantumwise.com/casestudies/ag_si_interface/ag_si_interface.html

In Projected local density of states part, it mentioned that
Quote
Moreover, the averaged potential nicely follows the conduction band minimum, both at the interface and far from it.

My question is how draw the line of valence band max maximum along the C direction ?

Thank you very much!

Any one can help me? Thank you very much !

Offline Daniele Stradi

  • Supreme QuantumATK Wizard
  • *****
  • Posts: 286
  • Country: dk
  • Reputation: 3
    • View Profile
It can be done with some atkpython scripting, but unfortunately at the moment we don't have a working and tested script for that.

Essentially, what you want to do is:

1) for each value of Z, the cell size length, calculate the ProjectedLocalDensityOfStates
2) extract the energies and the values of the PLDOS
3) scan the energies of the unoccupied levels of the PLDOS from the Fermi level to find the index at which the value of the PLDOS gets above a certain user specified threshold (e.g. 0.001 eV-1)
4) calculate the energy at that same index. That energy correspond to the value of the CBM at that particular value of Z

Regards,
Daniele.