Questions tagged [vasp]
For questions about use of the Vienna Ab initio Simulation Package (VASP).
334
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how to make a movie of the molecular dynamic simulation with many XDATCARs?
because I have about 200 CONTCARs and XDATCARs. How do I know which one I have to use to make a movie?
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How to create the supercell to simulate a disordered solid solution?
I am trying to simulate the DOS of a disordered semiconductor (Cd0.5Zn0.5S), my plan is to get the .cif file of CdS first, and build a supercell, then I should ...
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SOC calculations in VASP
I have a question regarding spin-orbit coupling (SOC) calculation in VASP.
For applying SOC in any system, should tags related to SOC be included in relaxation or in the SCF cycle? If it is in the SCF ...
5
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1
answer
803
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Why does VASP use -O2 optimization by default rather than -O3?
When compiling VASP, I am wondering why the
OFLAG = -O2
is suggested as default. For performance reason, I would use
...
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4
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Scripts to calculate ionic diffusivity
I found several AIMD analyzers to estimate mean square displacement and ionic diffusivity such as pymatgen, mo, vaspkit. I tried some tests and found that the same data set might result in different ...
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spin-texture by PyProcar
I am trying to plot spin-texture by using PyProcar code
pyprocar.fermi2D('PROCAR', outcar='OUTCAR', st=True, **energy=0.60**, noarrow=True, spin=1, code='vasp')
-...
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Number of kpoints vs Number of electrons
When using plane-wave codes for solid-state calculations, which computational parameter is more significant in increasing the computational cost: number of electrons or number of k-points?
I ask this ...
- 129
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Electric field calculations VASP
Does anybody have experience in electric field calculations using vasp? I gave the electric field to an already relaxed structure and it shows 'electronic self consistency is not achieved'. I even ...
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Elastic constants calculation
I am doing elastic calculations using VASP code in which
OUTCAR contains four different elastic moduli: ELASTIC MODULI , ...
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How to output Berry connection and identify the gauge by changing VASP or QE source code?
Usually, the first-principles packages like VASP and QE involve many aspects to totally figure out what their subroutines do. For example, to output Berry connection $\mathcal{A}^\alpha_{nn}$ used by ...
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Spacing issues about multiple-layer bcc structure
I am trying to make Hartree potential of bcc Tungsten(001).
My software is VASP.
5-layer should have 5 bound states.
But I don't have them
I heard it is a layer-layer spacing issue.
I built slab of ...
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How can I apply symmetry operations to wavefunctions obtained via VASP to map them to the whole BZ from the irreducible wedge?
I have developed a Python tool that extracts the plane wave coefficients and Gvectors from a WAVECAR file and I'm able to get the real space wavefunction for that ...
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Tips for using Hybrid Functionals in VASP
I am planning to use HSEO6 to calculate the band structure and DOS of a perovskite super cell. My cell has about 80 atoms. Furthermore I have also used dispersion correction and I will also have to ...
- 1,551
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study of elastic properties under pressure using VASP
I want to replicate this paper, but somehow I cannot get the same results, most important as shown in table 2. Can anyone help me with this?
I have attached the INCAR file. If any correction is needed,...
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VASP DFT+U on Ti d orbital, why d orbitals are not affected but s and p orbitals are pushed lower?
I'm using DFT+U implemented in VASP to calculate the electronic density of states of anatase TiO2.
In order to more accurately reproduce the experimental bandgap of anatase TiO2 (as compared to ...
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113
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Setting MAGMOM in VASP for possible Magnetic configurations
I have been working with a material in which Cu has an unpaired electron due to which the material can exist in various magnetic configurations. I wish to see how various properties change as I switch ...
- 1,551
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VASP structure relaxes to an incorrect ground state
I am using VASP to perform a structural relaxation of $\ce{CuNCN}$. I am using the PAW-PBE POTCAR files for the same and the KPOINTS have been generated using a script. The POSCAR file has been ...
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How to carry out spin texture calculation( as shown in figure)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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DFT-D2 calculations in VASP and Gaussian
We are planning on comparing the results of Quantum dots and Bulk materials for our systems so we are planning to use Gaussian for QD and VASP for Bulk. Considering that we will be comparing their ...
- 1,551
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121
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How to transform the k coordinate into the k path used in the band structure?
When drawing the band structure, I need to transform the coordinate of k-points into a k-path, but I am not sure what the formula is.
I checked the result of siesta,...
- 1,661
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Anti ferromagnetism of the Entropy Stabilized Oxide (ESO)
I want to do a simple SCF calculation for an entropy stabilised oxide using VASP (DFT code). The chemical formula is (CuCoMgNiZn)O (Rock salt structure) and it is anti-ferromagnetic in nature. I am ...
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how to choose a basis set when calculating COHP? [closed]
I am trying to use the lobster program to calculate COHP, according to the explanation in the literature, it is better to add unoccupied atom orbitals into the basis set.
The initial step in ...
- 1,661
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Is it possible to build a force field that suits all elements based on vasp's machine learning result?
I have tried to use VASP's machine learning force field calculation during running molecular dynamics simulation with a supercell including some elements of Ti, O, Cu, etc. It does increase the speed ...
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Coulomb energy in VASP
In DFT, the Coulomb energy is defined as the sum of Hartree energy, nuclear-electron attraction, and nuclear-nuclear repulsion. In VASP output, we can find the Hartree energy, and also the nuclear-...
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Why does the GPU version of VASP consume a lot of time on STRESS calculation?
I am trying to compare the CPU and GPU versions of VASP.6.3.0, it seems that the GPU version consumes a lot of time on the STRESS item, does it represent the time for calculation stress tensor?
Here ...
- 1,661
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How do I find out the subdivisions N_1, N_2 and N_3 in BAND STRUCTURE?
I want to find out how to get subdivisions from vasprun.xml of Brillouin zone. Does anyone know how to do this?
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What is the best cell shape to calculate the energy of a free atom with a periodic DFT code (VASP)?
I want to study the adsorption energies of many different atoms to some surfaces. For that, I need to calculate the energies of free atoms (adsorbates) in a vacuum.
I understand that I am supposed to ...
4
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1
answer
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Why I have difference between DOS and BAND gap?
As they advise everywhere, SKF should be considered without SOC, and already in NSCF, spin-orbit interaction should be included. But what is the actual question, as I know, band splitting occurs with ...
- 61
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4
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DFT code for simulating thousands of atoms in a supercell
I'm trying to simulate a supercell that contains thousands of atoms with the DFT method, but it seems VASP couldn't handle such a large system, its parallel efficiency is relatively low, when I try to ...
- 1,661
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density of state with spin orbit coupling
I have been doing DOS calculations with SOC tag on in VASP, and another calculation without SOC. As shown in the figure the DOS with SOC seems strange! is this wrong? How can I have resolved
I have ...
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how to simulate the size effect with DFT theory?
I am considering simulating the size effect of nanoparticles, the size expands from 0.2nm to 50nm, but when trying to build the model, I am not sure how to reflect the size correctly, for example, if ...
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How to save the generated 3d representation of the structure(s) by Viewer3d in Py4vasp?
I used py4vasp to calculate structure from data and then I displayed them in a structure viewer (Viewer3d) by this line: calc.structure[:].plot(). It returns a ...
6
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How to do simulation when two atoms exist in the same coordinate position in the lattice?
I found that there is a type of substance in which two atoms exist in the same coordinate position in the lattice, for example, FeF3(H2O)3, here is its crystal ...
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Effective mass of holes was measured using DFT
Effective mass of holes was measured using DFT. The hole value is different for each band, is there a way to get the average or standard value of this value?
It was calculated using the VASP program.
...
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252
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Why can't DFT calculate the accurate electronic configuration of the Oxygen atom?
I am trying to do a DFT calculation of Oxygen atoms with the VASP code. My settings follow the official tutorial on the Oxygen atom of VASP. But it turns out the energy levels of the two spin ...
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How to calculate the Gibbs free energy for a reaction?
I am trying to learn how to calculate Gibbs free energy for a reaction. Assuming a reaction for two-dimensional TMDCs:
MoS2 (solid) + 2Se(gas) ---> MoSe2 (solid)+ 2S (gas)
I can calculate the ...
- 1,366
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Scaling and speedup of Real-space based DFT calculations using Finite Elements approach
I have recently encountered paper where the authors have formulated Kohn-Sham equations using the finite-element package deal.II.
It stated in paper
DFT-FE was significantly faster than QE for all ...
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2
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108
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How to calculate temperature dependent phonon band structure in VASP
I want to calculate phonon band structure using VASP for a double perovskite $\ce{A2BB'X6}$.
Most of the perovskites are well known for dynamical instability at $\pu{0K}$ but show a dynamically stable ...
- 1,643
2
votes
1
answer
153
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NCORE bigger than 1 when performing phonon/vibrational calculation(IBRION=5) in VASP?
When I try to calculate the vibration frequency of TiO2, I set IBRION=5 in VASP, but it turns out I couldn't use NCORE>1 in this situation, once I use NCORE>1, VASP would run for only one ionic ...
- 1,661
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The ionic step is not convergent when doing DFPT in VASP
I am trying to do DFPT, during the process of moving in different directions, even I set EIDFF=1E-8, the corresponding ionic step is not converged, the relative ...
- 1,661
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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 ...
- 1,661
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Gibbs free energy modification after finishing NEB?
I have finished the NEB calculation, but it seems all the energy I got is Internal energy instead of Gibbs free energy, so do I need to do Gibbs free energy modification? Is there any standard ...
- 1,661
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335
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Reciprocal lattice and k-lattice belong to different groups in VASP
I am trying to do geometry optimization of TiO2 with VASP.
Here is the POSCAR file, which I get from the Materials Project.
...
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4
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273
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Why does the temperature fluctuate severely during the AIMD using an NVT ensemble?
I am trying to raise the temperature of my model and keep the temperature at 300K, with an NVT ensemble and Nose-Hoover thermostat.
I am doing this job with VASP, here is the ...
- 1,661
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83
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Rashba effect and VASP
How to prove by first-principles DFT calculations that the compound has Strong spin-orbit coupling and Rashba effect
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104
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Problem while performing the BSE GW calculations in VASP
I am trying to learn the BSE GW calculations in VASP. Using the procedure described on the VASP website.
I am stuck at the last step 5 (BSE calculation). I didn't get any error in the 5th step but ...
3
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answers
74
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band structure and primitive cell
When I use VASPKIT tool or SeeK-path to generate K-path file for a band structure calculation, it gives a PRIMCELL.vasp file , which has a unit cell that is ...
- 515
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1
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92
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Elastic constant calculation
I want to calculate elastic constants with VASP "by hand" (not by, e.g., DFPT) as I have a big structure (64 atoms). For this, I am making tests on $\ce{Si}$ at the moment.
So, I have done ...
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"Failed" running DDEC6 Atomic Charge when using Palladium (Pd) cluster model
I have a problem with running DDEC6 when I used Palladium (Pd) cluster, the main issue was that there were no DDEC6_even_templered_net_atomic_charges.xyz files came ...
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