Questions tagged [vasp]
For questions about use of the Vienna Ab initio Simulation Package (VASP).
157
questions
7
votes
2answers
98 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 ...
4
votes
0answers
33 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
65 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, ...
11
votes
1answer
46 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
38 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
39 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
71 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
98 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?
4
votes
1answer
101 views
How to interpret spin density isosurface figures?
The figure below shows the spin density isosurfaces of 3x3x1 ScS2 monolayer supercell doped with Mn atoms. This figure was generated using VASPKIT and ...
6
votes
1answer
38 views
What is the meaning of EATOM tag in the POTCAR files of VASP?
I am wondering what is the meaning of EATOM tag in the POTCAR files of VASP. What is its relationship with the energy of an ...
6
votes
1answer
80 views
What is the best setting for this workstation to speed up VASP calculations?
I am working on HP workstation with :
128 GB of RAM
INTEL(R) XEON E5-2620 V3 with 12 cores
What are the best settings of NCORE, ...
8
votes
1answer
52 views
Calculation of linear coefficient of thermal expansion using VASP-Phonopy for Hexagonal material
We use quasi-harmonic approximation using VASP-Phonopy. In whole calculation we only assume Free energy as function of volume but in case of HCP material which have ...
7
votes
0answers
41 views
Single electron transfer periodic DFT in VASP
I have the following question: I am currently studying the electrocatalytic CO2RR on Cu materials using periodic DFT calculations and I am using the CHE model to describe the proton electron transfer ...
5
votes
1answer
53 views
Divergence behaviour of surface energy
By definition, the surface energy of a thin film or a slab model is defined as
$$
\sigma = \frac{1}{2A}(E_{slab} - N\cdot E_{bulk})
$$
where $N$ is the number of atoms in the thin film and $E_{bulk}$ ...
5
votes
1answer
64 views
How do I extract the wave function from a VASP calculation?
We can obtain a energy band structure of a crystal from a DFT calculation in Vasp. Each point in each band represents an energy eigenvalue with a corresponding wave function from the Schrödinger ...
5
votes
1answer
66 views
Formation energy calculation
I am trying to calculate the formation energy of $\ce{Mg2Si}$ and for the calculation of lowest energy configuration of Bulk $\ce{Si}$: $E(\ce{Si})$ and bulk Mg $E(\ce{Mg})$. I have opted for both ...
8
votes
4answers
2k views
How do I search for a particular string in Linux?
I want to search for a value in the VASP OUTCAR file i.e the format of the line should be
Volume of Typ 1: 98.5 %
What ...
8
votes
2answers
300 views
What is the maximum allowed doping concentration?
Let's consider an example of a 3x3x1 supercell of WS2 monolayer which has 9 W atoms. If we substitute two of them with 2 dopants, the concentration will be 2/9 ...
7
votes
1answer
58 views
How to calculate E_TM in the formation energy formulas?
I found in the literature that the formation energy of doped supercell (e.g.: 4x4x1 supercell with one dopant atom) has many formulas, and the most common one is :
$...
6
votes
1answer
64 views
How to set NCORE, KPAR and NBANDS to speed up calculations on VASP?
I am searching of how to set the tags NCORE, KPAR and NBANDS on a specific systems to speed up calculations. Could you please tell me the rules to follow ?
8
votes
1answer
53 views
How to solve this Bandup software problem?
I have compiled the Bandup software using this command : ./build -compiler gfortran. After that, I tried to follow the tutorial inside the directory ...
5
votes
1answer
38 views
Regarding POSCAR file for bulk Silicon
I am newbie to DFT and I am trying to understand the different input parameters in the VASP POSCAR file of bulk silicon system, provided in the examples here. I am trying to find the lattice constant ...
5
votes
2answers
67 views
What is the RWIGS value for the DOS calculation in VASP?
I want to set the RWIGS value in the INCAR file for the investigation of the density of states (DOS) of $\ce{Mg2Si}$ so what ...
7
votes
1answer
97 views
How to set different exchange correlational functionals in VASP?
I want to test different exchange correlational functional on Magnesium silicide to investigate the electronic properties. For example, if I have the POTCAR library ...
10
votes
1answer
125 views
How to visualize spin density isosurfaces?
What is the package used for visualization of spin density isosurfaces in VASP like the ones shown below? A simple example/tutorial would be very appreciated.
7
votes
1answer
81 views
Band structure calculation
I want to do band structure calculation of Magnesium silicide for GGA in VASP. Can anyone please help how to do this by setting initial ...
7
votes
1answer
55 views
VASP input file for formation energy calculation
I want to calculate the formation energy of $\ce{Mg2Si}$ using VASP. What should be the initial steps to perform this run? What INCAR tags are required? Any help ...
4
votes
0answers
30 views
What are the TS, MBD keywords for new (5.4.+) VASP versions?
I tried IVDW = 2202 for MBD as mentioned on the website but I got the following error:
...
9
votes
1answer
138 views
SCAN-RVV10 geometry optimization
I'm using SCAN-RVV10 to optimize the hexagonal-BN but the optimized geometry doesn't look true as the calculated interlayer distance is far smaller than the experimental value(exp=3.35 Aangstrom, calc=...
8
votes
1answer
45 views
What are the input parameters of VASP for 2D material geometry optimization?
Apparently, my input parameters are not good for geometry relaxation of 2D materials using VASP.
...
6
votes
1answer
110 views
VASP error when trying to do calculations in the presence of an electric field
I am trying to observe the effect of the electric field on 2D materials. I applied electric field by introducing three tags:
...
11
votes
1answer
197 views
Number of KPOINTS in irreducible part of Brillouin zone
I want to investigate the comparison of Total Energy per cell with respect to the number of KPOINTS in the irreducible part of the Brillouin zone but I do not know ...
6
votes
2answers
215 views
How to perform band-structure unfolding in VASP?
I have created a band structure for 3x3x1 doped-supercell using VASP, and I obtained the figure below. Now I want to do band-unfolding. What are the simplest ways ...
8
votes
1answer
170 views
Single point energy calculation in VASP
I want to do single point energy calculations in VASP for $\ce{Mg2Si}$ so what should be initial steps to do? What are tags required in INCAR sufficient to do this ...
7
votes
1answer
107 views
Molecular Dynamics Simulations in VASP
I want to run molecular dynamics (MD) simulations with VASP for Mg2Si to investigate the simulation time vs ENCUT and KPOINTS, ...
6
votes
0answers
59 views
Phonon Frequencies and Free Energy with respect to polymorphs
I have a material that can crystallize in either a cubic or tetragonal polymorph depending on the synthesis. I used DFPT in VASP and calculated the phonon band structures. I see that the cubic has all ...
10
votes
1answer
123 views
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 ...
6
votes
0answers
53 views
In VASP, which option is better for monolayer relaxation: ISIF=3 or ISIF=4?
Since I have started working on monolayers I was using the ISIF=3 tag for relaxation, this was after recompiling VASP with the modified "...
6
votes
2answers
93 views
Bash script to extract lattice parameters from CONTCAR
I am using VASP to calculate material properties. I want to know how to extract the lattice parameters from my cells automatically with a script. I know about the method with VESTA (described here How ...
5
votes
1answer
84 views
How to do VASP convergence tests, and how to get two plots of Encut and k-points wrt to total energy? I want to do convergence for Mg2Si
I am using VASP for the first time and do not know how to do convergence tests. How are convergence tests done in VASP and how do we get two plots of Encut and k-points with respect to total energy? I ...
8
votes
1answer
93 views
What is the source of error in this mBJ-LDA calculation?
I am trying to do MBJLDA calculation for bandstructure for WS2 monolayer unit cell using VASP and following the method provided here : Band Structure mBJ-LDA using Vasp, but I am getting an error ...
7
votes
1answer
113 views
How to study a new material without any experimental data about it?
My question is a little bit general. I want to study a 2D monolayer material which hasn't any experimental data available, just some first principles DFT works using PBE, LDA and HSE06 (for band ...
8
votes
1answer
101 views
How can I find the binding energy for exciton (optical gap) with VASP?
What is the best way to find the binding energy for exciton using VASP?
I have heard about the method of calculating it through the dielectric tensor with local ...
6
votes
1answer
95 views
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
5
votes
1answer
95 views
How to calculate the enthalpy of formation?
I am following this paper to calculate the formation enthalpy of MgCu$_2$, in which the formation enthalpy is defined as follows:
where $E$(Mg$_x$X$_y$) is the total energy of the compound, and $E$(...
5
votes
1answer
34 views
Are these settings for HSEsol accurate enough?
I have conducted HSEsol relaxation on a monolayer unit cell of 3 atoms using VASP, with the settings below :
...
7
votes
1answer
76 views
Will there be a difference between GGA and GGA+$U$ for material with Sc element involved?
I have a material that contains the transition metal element Sc [3$d$1], and I want to know your opinions if there will be a difference between GGA and GGA+$U$ calculation. Knowing that the other ...
9
votes
1answer
102 views
How to perform HSEsol in VASP calculations?
I want to perform HSEsol (PBEsol + HSE06) calculation on a material (monolayer) that doesn't have experimental data available. Could you please tell me how to ...
7
votes
3answers
266 views
How to determine the value of the difference (U-J) in “Dudarev's approach” for GGA+U calculation using the VASP?
I want to conduct GGA+U calculations using Duradev's approach in VASP code on a ...
5
votes
1answer
37 views
Fermi level shift downward in the thin film structure
I did a band structure calculation of a thin film structure with different number of atomic layers. I found that the original bulk gap was shifted upward and the Fermi level was shifted downward no ...
