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Questions tagged [defects]

For questions about modeling material defects (e.g. vacancies, interstitial/substitutional impurities, topological defects).

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How to interpret defect formation energy diagram?

Why are formation energy diagrams typically plotted as a function of Fermi energy, and how should one interpret the changes in the x-axis before the charge state changes in these diagrams? Figure ...
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5 votes
2 answers
85 views

Why my Relax calculation is not stopping?

I am conducting a relaxation calculation on a mono-layer of MoS2 with a 3x3x1 super-cell, where one Molybdenum (Mo) atom is substituted with a Palladium (Pd) atom defect. However, the calculation is ...
Joyal sunny's user avatar
1 vote
0 answers
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Interstitial and vacancy defects

I'm trying to insert interstitial defects in an FCC crystal with 32 atoms. And also a quick way of inserting a vacancy or doing a substitutional defect. Any code for this would be deeply appreciated. ...
Nana Kofi Boakye's user avatar
4 votes
1 answer
346 views

Charged defects in siesta

I want to calculate defect formation energy for a substitutionally doped system (bulk) in a charged state. Is it possible to do such calculation using SIESTA code? If yes, what changes do I make in my ...
sushil's user avatar
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4 votes
1 answer
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Calculation of charge defect formation energy

I am confused about the calculation of the charge defect formation energy equation with these two terms (from figure below): $\Delta V$: alignment term, and $E_{corr}$: correlation term. How can I ...
 李思聪's user avatar
6 votes
1 answer
139 views

What is the procedure for calculating the formation energy of a doped material?

To calculate the formation energy of a material AB with 2 atoms, I created a 2x2x2 supercell, resulting in a total of 16 atoms. Then, I removed one atom of type A from the supercell. From the ...
Camilla's user avatar
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8 votes
1 answer
1k views

Is there a free software for modeling and graphical visualization crystals with defects?

At real situation, it can happen, that a crystal can have defects, for instance, some of them are point defects — Schottky, Frenkel defects, line defects — dislocations, planar defects — grain ...
SFriendly's user avatar
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3 votes
0 answers
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How to calculate the formation energy of a defect using the unit cell? [duplicate]

I want to dope CuI conventional unit cell using Quantum ESPRESSO. In previous papers they used different formulas of defect formation energies,and they use supercell. So I'm confused. What's the ...
Camilla's user avatar
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3 votes
1 answer
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How to determine defect charge state degeneracies?

I am doing defect calculations using the SC-FERMI package. However, one of the inputs is the degeneracy of the charge states of each defect. I know degeneracy is the number of states with the same ...
rmza7's user avatar
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5 votes
2 answers
612 views

Which formalism is better suited to model a crystal with defects: Hartree–Fock, Kohn–Sham, or something else?

Let’s suppose that (1) it’s required to calculate a crystal with certain parameters of a crystal lattice; (2) this crystal has some defects (let it be Frenkel defects for simplicity); (3) these ...
SFriendly's user avatar
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4 votes
1 answer
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Decide the position of oxygen vacancy via the configuration with the lowest energy?

I am trying to determine the position of oxygen vacancy in $\ce{TiO2}$, is it reasonable to decide it by choosing the configuration with the lowest energy? It doesn't feel quite right to always choose ...
Jack's user avatar
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8 votes
0 answers
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How to distinguish between deformation mechanisms in creep experiment? [closed]

As I'm learning more about viscoelasticity and creep experiments, I'm trying to understand how to distinguish between the different deformation mechanisms. In general, when a sample of viscoelastic ...
ValientProcess's user avatar
10 votes
0 answers
529 views

Difference of high-frequency and static dielectric constants? [closed]

I found in an article [1] the following definition of FNV (Freysoldt, Neugebauer and Van de Walle) energy correction term for a charged defect in a cubic supercell: $$E_{\text{corr}}=\frac{\alpha_Mq^2}...
Rogério Gouvêa's user avatar
7 votes
1 answer
86 views

Relax vs VC-Relax for interstitial incorporation energy

In order to model an interstitial trapped in a metal lattice, and the associated incorporation energy, which should be used - "relax" or "vc-relax"? I want to understand the ...
Dr.Viper's user avatar
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12 votes
1 answer
488 views

How to start with structural defects in monolayer?

First of all, thank you for your help! You are so helpful every time. I would like to calculate the influence of the structural defects on the electronic structure in the HfS2 monolayer. With VESTA ...
M_Fisher's user avatar
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24 votes
0 answers
488 views

What are the tools available for point defects calculations? [closed]

It would be appreciated if you could explain one of the tools below (or another tool not listed), in the format used here (for example): What software will allow me to combine two images? What ...
Franksays's user avatar
  • 501
16 votes
1 answer
83 views

What are good resources to study crystallographic defects in different dimensional systems and their topological dimensionality?

I wonder if there are any books or resources that may address one or more of the following questions: What kinds of defects are important for topology? Especially crystallographic defects. How do ...
Siddhant Singh's user avatar
19 votes
1 answer
1k views

What are some approaches to modeling charged point defects in materials?

From what I understand, one major issue in modeling charged point defects in materials is the existence of artificial interactions between charged defects and their periodic images. Even when using ...
Stephen Xie's user avatar