Questions tagged [band-structure]

Questions about the band structure of solids. Band theory forms the foundation of the understanding of all solid-state devices.

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6
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0answers
34 views

Is it possible to construct a tight binding matrix of high atomic layer thin film from the lower one?

Give a tight binding matrix of a few atomic layer thin film system, is it possible to construct a tight binding matrix of higher atomic layers thin film from the lower one? For example, I have a 4 ...
10
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1answer
82 views

What does a density of states (DOS) plot show?

I have plotted the density of states using GGA-PBE exchange correlation functional for magnesium silcide but I really do not know what the equations involved are in this process, and how they relate ...
8
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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 ...
8
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1answer
46 views

How to calculate the parity of a band at a particular point in Brillouin zone

Some references mentioned that the calculation of $Z_2$ topological invariant of a crystal can be greatly simplified if the crystal contains inversion symmetry. But it involves the calculation of the ...
6
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2answers
201 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 ...
6
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1answer
60 views

Calculating the surface state with Wannier tools

Currently I met a problem when I calculate the surface state of a topologically non-trivial thin film system. I did a DFT calculation and fit the result with wannier function. The fitting looks pretty ...
8
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1answer
85 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 ...
10
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2answers
115 views

k-points value in KPOINTS file for the VASP band calculation

I'm a new VASP user, especially for the band structure calculations. I see that KPOINTS files are different for the GO/SP calculations and band calculations. For example in here it shows KPOINTS file ...
6
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2answers
46 views

Does SOC band structure calculations require higher number of k-grids?

In so many papers I see that they carry out soc band structure calculations with much higher kgrid than used for the geometry optimization. Whats the logic behind that?
4
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1answer
52 views

How can I obtain seperate spin-up and spin-down bands while considering Spin Orbit Coupling in Quantum ESPRESSO?

I have been studying a magnetic material with SoC taken into consideration. The main aim was to obtain the band structure. when I use spin_component = 1 in the ...
11
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1answer
44 views

How can I properly attach ligands to a surface?

The main aim of my venture is to study the effect of the presence of surface ions on the band structure of Si slab using Quantum ESPRESSO. I've tried to use iQmol to attach ligands to the surface. The ...
5
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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 ...
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39 views

A doubt about extended dislocation

I wonder why this phenomenon occurs: "Unlike unextended screw dislocations, the extended screw dislocations define a specific slip plane, the {111} plane of the fault and it will be constrained ...
8
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0answers
61 views

Band structure has unusual lines in the valence band using Quantum ESPRESSO

Currently, I am working on ZnO doped with nickel and cobalt. I performed the SCF, NCF, BANDS calculation and got the results, the calculation converges without any errors. After that I used BANDS.X to ...
7
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2answers
186 views

What is the meaning of the “PRIMCELL.vasp” file generated by VASPKIT tool during bandstructure inputs generation?

When I use VASPKIT tool to generate K-path KPOINTS file for Bandstructure calcualtion of a 4x4x1 supercell of a pure material, ...
6
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0answers
62 views

Calculating the Chern number on a 2D surface of a 3D insulator

I want to calculate the Chern number of a surface of 3D time reversal insulator. I know the 3D topological insulator was characterised by the Z2 index. And the Chern number was used characterised the ...
10
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2answers
133 views

How to create a KPOINTS file (k-path) for 4x4x1 supercell bandstructure calculation?

How to generate or create the correct KPOINTS ( K-PATH) file for a 4x4x1 supercell bandstructure calculation ? Is there a software compatible with vasp can do that ?...
6
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1answer
48 views

Band structure output from Exciting - what are the X units?

I'm using Exciting Code to calculate some electronic band structures. Starting with the example of Si I get sensible output and can plot BAND.OUT and BAND-QP.OUT using PLOT-gwbands.py or directly in ...
10
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2answers
125 views

About the surface Greens function method for calculating the surface state

Currently I'm using some software package to do the data analysis from the DFT calculation so that I can study the surface state of some topological insulator. I found that the method they use is ...
9
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1answer
126 views

PT-symmetry leading to spin-degenerate band structures

I am trying to understand the fundamental physics of a kind of problem. I will introduce a specific example and then list some of the broader qualms I hold. I have observed many band structures, be it ...
10
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1answer
131 views

Band structure of Weyl semimetal?

Weyl semimetals are topological quantum materials whose low energy excitations emerges as massles Weyl Fermions. They have a band touching point near the Fermi level called Weyl node. What is ...
10
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2answers
80 views

Spin considerations for the bandgap and optical excitations

What are the consequences for the bandgap if the conduction band edge and valence band edge are contributed by different spins? Are there any driving forces that prevent an excitation from spin up to ...
12
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1answer
136 views

Band structure and density of states disagreement (mp-19092)

My question is both specific and general. While looking through the materials project database I found this entry. The band structure reported and density of states are dramatically different it ...
8
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1answer
75 views

Band theory: effective mass and Hall's coefficient

Consider the following scenario. A material has the E-k band scheme as shown in the figure (extended scheme of zones). Could anyone give me a suggestion regarding the following : Electrical character ...
7
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0answers
83 views

The gap was open when I was doing an HSE + SOC DFT calculation

I used VASP as my DFT software to do a calculation on an anti-perovskite crystal. I try to reproduce the band structure from literature which was calculated based on HSE + SOC calculation. Their ...
11
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1answer
575 views

Density of States of Supercells

Are there any important considerations to make for density of state calculations for supercells? With band structures typically band unfolding schemes make things easier to understand but is there ...
13
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2answers
160 views

Deciding the number of CPUs for a DFT calculation for band structure in Quantum ESPRESSO?

If I am using Quantum ESPRESSO for bandstructure calculations, how can I know the number of CPUs necessary for such a calculation? I deal mostly with ternary transition metal oxides which have at ...
15
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1answer
210 views

How to separate the data plot for spin up and spin down band structure into 2 different graphs, in Pymatgen?

I am a beginner user of the Pymatgen package. In order to process the data from VASP DFT calculation software, I use Pymatgen to visualize the output band structure. When I do spin polarised band ...
10
votes
1answer
179 views

How to model an anti-ferromagnetic crystal in quantum ESPRESSO properly?

I'm fairly new to DFT. I would like to plot the DOS and band structure of Cobalt Oxide (CoO). But since CoO is anti ferro magnetic, how would I approach the problem? would I create an input file ...
10
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1answer
88 views

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 ...
8
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1answer
155 views

Spin polarized DFT calculation in Quantum ESPRESSO

I am trying to run spin polarized DFT calculation on system Ti2FeSn. I am doing vc-relax calculation to relax the unit cell but having problem to converge total energy. Total magnetization is also ...
6
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1answer
55 views

How to understand effect of increase in band gap generated away from Fermi energy on conductivity?

An example would be that when we dope Nitrogen in graphene its conductivity decreases. This can be explained through other means. But can this be explained through the change in its band structure?
5
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1answer
58 views

How to separate the band structure of different materials in heterostructures using Quantum ESPRESSO?

So, I know that to calculate surface band structure of a material, you have to take its 2D system eg. single or few-layered. But, how to find the surface band structure in the case of heterostructures....
5
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2answers
118 views

Calculating the band structure with different unit cell

I have to do a electronic band structure calculation on a heterostructure using DFT calculation. First I do the calculation on each phase separately. I use a primitive unit cell to do the calculation ...
10
votes
2answers
444 views

Plotting density of states of Fe(BCC) using Quantum ESPRESSO

I have run the DFT calculation and plotted DOS of Fe(BCC) in Quantum ESPRESSO. I have attached the plot: (click on image to see clearly) But It's a wrong plot as it is not matched with the referenced ...
11
votes
2answers
827 views

Is there an energy gap correction factor that needs to be used in DFT calculations?

I am a beginner and have performed the DFT calculation in Quantum ESPRESSO for calculation of the direct and indirect bandgap of Silicon. I found the indirect bandgap to be 0.6551 eV. Now, I have ...
12
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1answer
384 views

Si energy band values are not matching with literature values

I have performed the DFT calculation for Silicon in Quantum ESPRESO. I have tried to calculate the electronic band structure, the shape of wiggles of bands are mostly matching but the energy values ...
11
votes
1answer
112 views

What's the crystal orbital Hamiltonian population?

What's the crystal orbital Hamiltonian population (COHP) or the crystal orbital overlap population (COOP)? What's the relation between the bandstructure or density of states (DOS) and COHP/COOP? Why ...
10
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5answers
1k views

How to know optimal K-points grid values for good DFT calculation?

I am doing DFT calculations with pw.x executable in Quantum Espresso. For this we have to choose right K-points grid in order to perform error-less calculation. But I have no idea about how can I ...
5
votes
1answer
163 views

How to implement scissor-correction in VASP to study optical properties?

It is mentioned here that It is possible to correct for the DFT band gap error by introducing an empirical scissors correction, which is effectively a rigid shift of the conduction band with respect ...
8
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2answers
134 views

Supercell band structure unfolding advantages

I understand that some codes allow for or have external tools to perform band unfolding in super cell calculations. Normally these codes give band structures that are somewhat grainy and not nearly ...
9
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1answer
176 views

Can the fermi level of a semiconductor be below the valence band?

I was looking at the data on this page for a NiWO4 calculation. I can see unoccupied bands near the fermi level that appear to be below the band gap. What does this actually mean physically or is it ...
11
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1answer
198 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 ...
7
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0answers
190 views

Calculating band structure with HSE using Open_grid (Quantum ESPRESSO) [closed]

I have executed the SCF calculation and obtained the results. After which I used kmesh.pl to extract k-points. I was able to run wannier calculations but there was an error Checking info from wannier....
12
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2answers
462 views

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 (...
16
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2answers
794 views

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?
9
votes
2answers
219 views

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 ...
9
votes
1answer
217 views

How to derive the k-path for monoclinic lattice structure?

Good afternoon all, My post is inquiring about the mathematical derivation behind the Monoclinic crystal structure (c axis unique). The Brillouin zone (BZ) I really would like to derive is shown below:...
8
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1answer
87 views

Physical origin for higher bandgaps when going from bulk to few-layers

This is a trend that's observed in most materials that I've observed. When you go from bulk to monolayer, the bandgap of the material increases: this is true for commonly studied materials like ...
9
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0answers
90 views

Is the non-trivial band topology in a system, caused by spin-orbit-coupling or band inversion? [closed]

How can we know that the non-trivial band topology in a system is driven by spin-orbit coupling (SOC) or by band inversion? Based on my understanding, SOC causes the band inversion and makes the ...