Questions tagged [vasp]
Questions about or related to the Vienna ab-initio Simulation Package (VASP).
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Create doped structures to POSCAR files for vasp
I have a perfect supercell structure Ni fcc. And I would like to dope another element O or N with a ratio of O:Ni=8:100 to the supercell of 3x3x3 and find the most stable ordering structure. The ...
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Quantum ESPRESSO vs VASP
We know that both Quantum ESPRESSO and VASP can perform lots of different kinds of simulations of materials. But what can VASP do that Quantum ESPRESSO can not, and vice-versa?
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3
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k-points and ENCUT convergence tests before or after relaxation?
Let's say I want to relax a structure using VASP. K-points and ENCUT convergence tests must be conducted before or after relaxation? and which tags should be ...
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3
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Geometry optimization for n-layers in VASP
What is the best way to optimize monolayer geometry in VASP?
Should the same method be used for an n-layer (n=2,3,4,5)?
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2
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How can I be sure that I have found the conduction band minimum in DFT?
Let's say I want to find the electronic energy bands from DFT calculations in VASP along a chosen path in the Brillouin zone.
Now, I want to make sure I choose a path that captures the conduction band ...
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1
answer
515
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Can a file in the Gaussian CUBE format be voxelized?
My aim is to voxelize a CHGCAR file. I am trying to build up a workflow to do the same. With the aid of the Matter Modeling community members, I have figured out a way to convert a CHGCAR file into ...
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2
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What are good ways to reduce computing time when working with large systems in VASP?
I know that parallelization is an important factor, however, I wanted to know if there are any other methods of reducing computing time when dealing with large systems without sacrificing accuracy.
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2
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What are some good band-structure/DOS plotting tools/styles?
I am currently using p4vasp for drawing DOS and band-structure plots, but it is not much handy in modifying the OUTPUTS. Could you please suggest any other good software or tools for that?
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9
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How to master Fortran with minimal effort?
Fortran language is used in many first-principles matter modeling codes, such as VASP and QE. These codes usually include many ...
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2
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What is the difference between Ultrasoft, ONCV and PAW Pseudopotentials? Which is better for a spin-orbit coupled calculation?
I am trying to do spin-orbit coupled calculations for various topological insulators. I have found papers using Quantum Espresso with ONCV pseudopotentials and papers using VASP with PAW ...
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What are the pre/post processing tools available for VASP?
I am aware of pyPROCAR and VASPKIT. Are there any other tools supporting VASP
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Are there problems with the Tran-Blaha modified Becke-Johnson potential (mBJ, a.k.a. TB09) in Quantum ESPRESSO?
I have used the modified Becke-Johnson (mBJ) exchange potential before, as it was developed and implemented in Wien2K by Fabien Tran and Peter Blaha (1). In 2013, Éric Germaneau et al. implemented mBJ ...
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How to make a k-point convergence test for a bulk structure with a lower k-point in the z-direction?
Let's say I want to make k-point convergence test for graphite. And let's say it converges at 12x12x4.
Do I first need to do a k-point convergence test for equal k-points on xyz directions then make ...
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2
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Parallelization in VASP
I have a system that has 1 k-point, 54 atoms, NBANDS=152, and NGZ=80. I'm running an AIMD simulation on VASP version 5.4.4
The ...
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11
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1
answer
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Simulated low energy electron diffraction (LEED) patterns
What modern software supports the generation of LEED patterns? It seems most LEED simulation packages are quite old and do not work on modern hardware. Is there something that prevents common ...
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How to carry out HSE06+SOC band structure calculation using VASP?
I could not find any good source for this type of calculation. I'd be very appreciated if someone who is experienced with that to show it step by step
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How to process electron-density data from a CHGCAR for better handling?
We all know that Vesta helps us visualize the electron clouds present in the CHGCAR data, but I am looking for a better way to process the electron-density data we get in a CHGCAR file for compact ...
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8
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1
answer
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How to evaluate the electron relaxation time of nanostructures computationally
I am working with Si nanowires using the SIESTA ab initio code and the BoltzTraP2 Boltzmann transport equation solver. However, the output of the BoltzTraP2 code comes per relaxation time (...
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6
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1
answer
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Different between ENCUT and ENAUG in the VASP setting?
I am trying to figure out the difference between ENCUT and ENAUG in VASP settings, I found the following description on the wiki of VASP.
ENAUG specifies the cut-off energy of the plane wave ...
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5
votes
1
answer
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Best practice(s) for q-points convergence in phonon density of states calculations
The answer can be a complete description of all the things we must be attentive to while converging q-points.
A peculiar thing that I feel contradicted about: Generally, we don't take an equal # of k-...
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1
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Calculation of DOS in HSE06
Do I do rest, scf, dos steps when calculating DOS like PBE in HSE06? Can anyone help me with this?
2
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0
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How to include the spin-orbit coupling strength of only two or three elements in VASP? [closed]
I am trying to calculate magnetic properties in my material with VASP, much like Fig 3b of this paper. The paper says:
"To understand the origin of the SIAin monolayer MnBi2Te4, we performed the ...
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Difference between potential energy, free energy and Coulomb energy in solid state physics
I often encounter terms such as (Helmholtz, Gibbs) free energy, potential energy and total energy when describing the energy of a physical system at atomic level. Sometimes I stumble upon Coulomb ...
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2
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Calculating binding energy between two systems
Regarding the calculation of binding energy of molecular absorption on graphene, for which this has been discussed before, the process of calculating $E_{AB}$ is fairly straight forward, i.e., it is ...
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17
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1
answer
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How to ensure a smooth band structure?
I performed an HSE06 calculations using VASP and the calculated band gap is in good agreement with experiment. However the band is not smooth, with very sharp, zig-zag like features. How to improve ...
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How does the mBJ potential give an accurate band gap as compared to LDA and GGA?
I am not able to understand the literature on how the modified Becke-Johnson(MBJ)$^{[1]}$ potential gives an accurate bandgap. Can someone please help? Thank you. The formula for the potential can be ...
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2
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How to start with the optical properties of 2D materials with the VASP code?
I hope you are doing well. I am new to VASP, and my project is "Optical properties of 2D materials on VASP" but I have no idea how to run a simple calculation with VASP. I will be very ...
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15
votes
1
answer
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Standard values for level of convergence
In matter modelling we use self consistent approaches for calculating different properties. Many DFT codes find the ground state of the system by determining total energy self consistently. Going ...
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1
answer
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Is LDA better than GGA for elastic constants?
I have calculated elastic constants for Si, GaAs, and GaN using LDA and GGA in VASP.
LDA is giving better results than GGA for elastic constants.
Is there is a reason behind the good results by ...
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14
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3
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How can I use a GUI on a supercomputer?
I am trying to make plots based to VASP simulation results, but I am struggling with how to download so much data from the server. A lot of examples on the internet are taught using the local desktop ...
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13
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2
answers
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mBJ-LDA band structure calculation using VASP
I tried to create a band structure with the mBJ-LDA method using VASP. I found information that the KPOINTS file should be created according to the "0-weight (...
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13
votes
1
answer
920
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Doubt about energy convergence with different k points
During the convergence test of k points, I observed my energy start increasing instead of decreasing. I am doubtful is this correct or I am doing something wrong. can I take the appropriate K point in ...
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1
answer
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Why is the Nonequilibrium Green’s function (NEGF) method for quantum transport not implemented in plane wave codes like VASP and Quantum Espresso?
DFT codes like Siesta, QuantumATK, Questaal, and Smeagol having localized basis sets have NEGF implementations available. But not in plane wave codes like VASP and Quantum Espresso. Why is it so?
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12
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1
answer
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Dealing with symmetry of ordered primitive cell during DFT structure relaxation
I have a large disordered cubic structure that I would like to do AIMD on to look at cation diffusion. I found the primitive cell and then ordered it to create several configurations. I will then ...
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12
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0
answers
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Correlation Functions in the Cluster Variation Method [closed]
I've been referring to Dr Mohri's paper [DOI: 10.1007/s11837-013-0738-5] for the cluster variation method (CVM). I wish to calculate the configurational entropy of a binary FCC system.
Cluster ...
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12
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1
answer
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Binding energy calculation for Zn atom on armchair graphene slab?
I am trying to repeat the result of this paper for Zn absorbed on the armchair graphene slab.
The relaxed top and side structures are the following:
The relaxed structure is almost the same as the ...
- 14.9k
11
votes
1
answer
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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 ...
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11
votes
2
answers
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Which properties of a material calculated using density functional theory are affected by smearing?
Smearing (smearing width $\sigma$, to be precise) has always been confusing. I understand what it is but can't pin it down when it comes to DFT calculations. Should it be converged like k-points and ...
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10
votes
1
answer
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How to remove the fake k-points from vasprun.xml file in the calculation of HSE06 band structure?
Is there any script that can remove fake k-points from a vasprun.xml file for HSE06 band structure calculation? Because removing it manually is a time-consuming ...
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2
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How to make a good HSE06 bandstructure for TMDC monolayer material (e.g.: WS2) in terms of VASP calculation INPUTS?
I want to perform HSE06 band-structure calculation of a WS2 monolayerwhich has the following POSCAR with ...
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10
votes
1
answer
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How to calculate the formation energy of a monolayer using VASP?
I want to calculate the formation energy of WS2 monolayer unit cell using VASP. I am wandering if you could show me the detailed ...
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answer
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Electric Field Calculations in VASP
Can someone share appropriate tags and method to apply Electric Field in VASP?
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1
answer
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How can we calculate the Gibbs free energy from first principles?
I am trying to calculate the Gibbs free energy for a bulk material. Since DFT ground state calculations give the energy at 0K, a temperature dependent part has to be added in this to obtain correct ...
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9
votes
2
answers
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Problem related to the calculation of elastic constant with VASP5.4.4
I am using VASP5.4.4 to calculate the mechanical properties of the cubic phase SnTe. The structure can be found in the materials project website.
In detail, I use the following INCAR to calculate the ...
- 14.9k
9
votes
1
answer
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How to extract lattice constants a and c from relaxed hexagonal structure using VASP?
Taking a bulk WS$_2$ (bilayer) structure and relaxing it with ISIF=3 and IVDW=10 (DFT-D2 method) using the VASP code. Then ...
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9
votes
1
answer
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How does charge mixing work?
When doing DFT calculations on certain magnetic materials, convergence can be difficult. This problem can be solved by changing the mixing parameters (e.g. AMIN and BMIX in the INCAR file of VASP). My ...
user5405
9
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2
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What is the format of the electron-density data in a CHGCAR file?
Rephrasing the above, what is the pattern in which the electron-density data is stored in the CHGCAR file?
I understand that the electron density data in a CHGCAR file is in the form of a 3D Fortran ...
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votes
1
answer
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Work Function Problem
2D materials (such as graphene) are mostly exfoliated from their 3D bulk counterpart. I am wondering how we can calculate work function for a 2D material? Normally electrostatic potential in the out-...
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votes
1
answer
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When to use pseudohydrogens to passivate a slab?
I often see some papers that don't use pseudohydrogen passivating the slab's bottom side when doing DFT simulation on the metal oxide's surface, for example, the following description is from a paper ...
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8
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2
answers
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Why don't we use the principal quantum number when building the projected density of state?
I am using VASP to calculate the projected DOS, but I am not sure why we aren't using the principal quantum number when doing the projection.
According to the VASP wiki, LORBIT would control VASP to ...
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