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Questions tagged [vasp]

For questions about use of the Vienna Ab initio Simulation Package (VASP).

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5
votes
1answer
69 views

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 ...
2
votes
1answer
50 views

Band Structure Calculation with HSE06 Hybrid Functional in VASP

I am using HSE06 hybrid functional to calculate the band structure. I copied IBZKPT file as the KPOINTS file and pasted the k point path for the band structure after this file. The k point path for ...
7
votes
1answer
44 views

Recommendations to treat 4f electrons (valence) of Yb3+ in magnetic systems in VASP

I need help with: I would like to know what is the most common approach to treat valence 4f electrons of lanthanides (3+ charge) in VASP that circumvents the calculation problems shown below. (or more ...
5
votes
1answer
40 views

Calculation of ionization energy for an alloy

How to calculate ionization energy for an alloy system (for eg. $\ce{Mg17Al12}$) using DFT?
3
votes
1answer
48 views

Determining conduction band minimum of a semiconductor

How can I determine the minimum of the conduction band of a semiconductor using DFT/VASP, or any other option?
3
votes
1answer
92 views

How to do lattice optimization, encut optimization and Kpoint optimization in VASP?

What is the procedure to do lattice optimization, encut optimization and kpoint optimization in VASP? Thank you in advance.
10
votes
2answers
175 views

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 ...
9
votes
2answers
63 views

Can these Band-gap specifications be attributed to a Half-Semiconductor material?

A Half-Semiconductor is a material with a narrow band-gap for one spin channel and a wide band-gap for the other channel. ...
8
votes
1answer
72 views

If Gaussian and Tetrahedron smearing method lead to different Fermi energies, which one is the correct?

In addition to this post, The used settings were : DOS: ISMEAR = -5 SIGMA = 0.2 (default value) BS: ISMEAR = 0 SIGMA = 0.1 Now,...
5
votes
0answers
38 views

How can I find primitive axis for any bulk or 2D (monolayer) material

I am doing DFPT calculations using VASP+Phonopy. To plot phonon band structure, I need a band.conf file in which we need to ...
7
votes
0answers
52 views

Why do I get negative charge density values in the core of atoms when I perform DFT calculations with PAW?

We are all aware of the fact that negative charge densities in the atomic cores are an artefact of Density Functional theory Calculations using Projector Augmented Wave (PAW) method. But what is the ...
4
votes
1answer
56 views

Optical properties without LOPTICS tag

I have performed some calculations for a 2D-monolayer using VASP. I run DOS calculations without LOPTICS = .TRUE. I found that ...
5
votes
2answers
91 views

What is the source of this band structure and DOS inconsistency?

Using VASP, I have conducted DOS and BS calculations of a Ti-doped $\ce{MoI3}$ monolayer using the following: POSCAR: ...
6
votes
1answer
119 views

Lattice vectors are misaligned and vacuum size is reduced, was my calculation successful

I did an optimization for a monolayer with GGA (550 eV ecut, 12 12 1 k-mesh) with ISIF=3 and IBRION=2. My original POSCAR was: ...
4
votes
0answers
60 views

HSE06+SOC calculation in VASP: How to remove false k-points?

I followed the steps mentioned in the answer of question: How to carry out HSE06+SOC band structure calculation using VASP but I found a zigzag band structure. Any idea how to remove false k-points in ...
3
votes
1answer
67 views

How to do a proper relaxation of the multicomponent structure?

I have a beta Ti (Space Group 229) structure with 16 atoms, I prepared 15 disordered TiNb structures with 5 atoms of Nb. I did it using VASPKIT. However, before the ...
5
votes
1answer
86 views

How to run multiples VASP files named as POSCAR-XYZ

Is it possible to direct VASP to read a POSCAR-xyz file instead of reading the default POSCAR? For example, I want to run VASP in the Quantum ESPRESSO format: ...
4
votes
0answers
30 views

How to correct units in the band.yaml file of QE, to band.yaml of VASP

I see from the phonopy web page 1 that the physical unit systems used for the calculators are different for different codes 1. On the same page, it is mentioned that "For these sets of physical ...
5
votes
1answer
37 views

What is the Quantum ESPRESSO equivalent for VASP's k-mesh sampling resolution?

$\require{mediawiki-texvc}$ Many authors in their research papers involving VASP, report for the k-mesh sampling with a statement like this: "Gamma-Centered mesh with a resolution of $2\pi \...
9
votes
1answer
193 views

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 ...
7
votes
1answer
71 views

Calculating the band structure of Bi2Se3 with spin-orbit coupling

I would like to simulate $\ce{Bi_2Se_3}$ using a DFT calculation on VASP. However, it seems I am not able to get a result; the electronic steps take $\sim \infty$ of time to complete. Here are the ...
4
votes
0answers
41 views

DFT Vasp calculation not converging when doing a SCF calculation for monolayer MoS2 [closed]

I am trying to calculate the electronic structure of Monolayer Molybdenum Disulfide ($\ce{MoS_2}$) using Vasp. However, I encounter problems with convergence. It does not seem that my calculations ...
4
votes
0answers
65 views

How to compile VASP without the flags -DNGXhalf and -DNGZhalf? [closed]

I'm trying to do spin-orbit coupling calculations with VASP but when I started to run them, I got this error: ...
7
votes
1answer
147 views

HSE06+SOC method using VASP

I have a query on HSE06 + SOC method in VASP. This is a follow-up question to the comment given for a similar question at: How to carry out HSE06+SOC band structure calculation using VASP? I haven't ...
18
votes
9answers
8k views

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 ...
2
votes
0answers
46 views

How to plot a charge density from a CHGCAR file in Python?

I can convert a CHGCAR file on the NxNxN grid into a 3D array of shape (N,N,N) for better handling, if that helps. At the end of the day, I want plot/visualize the ...
6
votes
1answer
302 views

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 ...
5
votes
1answer
49 views

Can a CHGCAR file be converted into a CIF file?

A .cif file can be used for multiple purposes and is a more generic format to store atomic data.
4
votes
1answer
96 views

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 ...
6
votes
2answers
210 views

POSCAR data file for a 2D system

I would like to understand how to calculate the band structure of the Graphene monolayer system using DFT. I am using VASP for material simulation. My question is how to write the crystal structure ...
7
votes
2answers
170 views

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 ...
6
votes
1answer
76 views

How to estimate adsorption energy of Li atom on graphene?

I would like to reproduce the data of adsorption energies published in paper. For example, they say the adsorption energy for Li atom on graphene is -1.19 eV (estimated by GGA-PBE). I used vasp (5.4) ...
8
votes
1answer
73 views

Benchmark test cases for DFT program or VASP?

Cross-posted on reddit/comp-chem. I am trying to build my workflow of using DFT to predict properties of some materials, but I am not sure if I do it all right, so I think there might be some ...
11
votes
1answer
89 views

Translating fractional coordinates resulting from conventional cell and primitive cell

I have calculated the band structure of some material where the unit cell was the conventional one (i.e. the lattice vectors are orthogonal). I'm trying now to calculate the same band structure only ...
6
votes
0answers
75 views

How to optimize the geometry of beta PHB in VASP?

I would like to calculate the elastic constants of beta PHB. From this paper. I know that it has P3221 space group. The beta PHB has upward and downward chains, which exist at one lattice site with 50%...
10
votes
1answer
227 views

Increasing k-point grid to take DOS calculation

I was trying to compute some electronic properties for Pd using SIESTA and VASP for some computer practicals in my university, specially focused on band structure and density of states (DOS) using LDA ...
7
votes
1answer
85 views

How to choose a different band path for band structure calculation using VASP?

How can I set a different band path for VASP calculation? For example I want to plot KGMK but not GMKG for graphene?
10
votes
1answer
90 views

Is there a database where one can find the Electron Density data of materials?

The database I am looking for may be experimental, computational or user-generated data. If I end up using the data, I will be providing the necessary citations and credits. Thank You.
7
votes
2answers
59 views

How to take periodic snapshots while running a simulation in VASP?

Same question, rephrased: What is the procedure to take snapshots at fixed intervals while running an AIMD or DFT Simulation in VASP? OR Which parameter in the INCAR file do I modify to achieve ...
8
votes
1answer
112 views

How to create the structure file for these materials?

I want to create a POSCAR or CIF file file for the monolayers with the data mentioned in the table below : Knowing that the spacegroup is : R-3 (148) Could you please create the POSCAR/CIF for these ...
5
votes
0answers
55 views

Should I add vdW interaction to estimate chemical potential of metallic elements?

I am considering layered oxides $\ce{LiCoO2}$. Previous papers suggested that vdW interaction should be added to get lattice parameters closer to experimental data. I would like to dope other elements ...
7
votes
1answer
189 views

How to generate Electron Density Fields using DFT?

How may I generate Electron Density Field information using Density Functional Theory calculations? What would my required inputs be like in VASP or Quantum ESPRESSO?
7
votes
2answers
148 views

Why is there a large discrepancy between calculated frequency dependent dielectric function and experimental measurement?

I am calculating the frequency dependent dielectric function of $\ce{SiC}$ using VASP. After a geometry optimization, the INCAR file below is used for the ...
9
votes
0answers
112 views

How to do a Sampling on the boundary of Brillouin zone in VASP

I use VASP to do my DFT calculation. I have to do a self consistent calculation to generate my CHGCAR. I want to ask is there anyway to write the KPOINTS file to generate K-meshing grid which can ...
9
votes
1answer
169 views

Why VASP calculates the elastic constant for another trigonal space group?

Please, help me to understand the problem. I calculated the elastic constants for the beta PHB (Space group P3221 (154)), it has to show the reduced elastic constant matrix (six), however, ...
12
votes
1answer
62 views

What does this temperature & total free energy profile mean (obtained from VASP NVT molecular dynamics simulations)?

In order to obtain molecular dynamics (MD) simulations trajectory for computing phonon dispersion relation at finite temperature, I performed NVT MD simulation using VASP for my target system. Here is ...
6
votes
1answer
57 views

How to make this DOS plot more smooth and add more points around Fermi level?

I have calculated and plotted the DOS for a doped monolayer 3x3x1 supercell. I want to make the plot more smooth and add more points around Fermi level. Knowing that these are my settings for the ...
8
votes
1answer
88 views

When import volumetric data (spin density of CHGCAR) to VESTA which option should we pick here?

I am trying to plot SPIN DENSITY isosurfaces using VESTA. I have used vaspkit option 312 to create ...
7
votes
2answers
238 views

How to use gnuplot to draw Bandstructure and DOS from VASP outputs?

I am wondering if you could show me how to use gnuplot to draw bandstructure and DOS plots starting from VASP outputs. If you have any scripts please share them with us. Thanks.
4
votes
1answer
245 views

How to change the spin-orbit coupling strength in VASP?

Since the effect of spin-orbit coupling plays an important role in a topological insulator, How to change the spin-orbit coupling strength in VASP?