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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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 ...
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Constructing the symmetry operator from k.p Hamiltonian

I have a question regarding to how to construct an operator from k.p Hamiltonian. Maybe there are some problems in my understanding, I hope you can point me out and correct my description if I made ...
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Nanowire Band Structure using Siesta DFT

I'm working with the Siesta DFT software, and managed to reproduce the band structure of bulk Si without any issues. However, when trying the same with a Si nanowire, the band structure looks nowhere ...
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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. ...
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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,...
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transition dipole matrix element

When doing DFT calculations of periodic solids, from either $\mathbf{k \cdot p}$ perturbation theory or simply using the trick $\mathbf{r} \rightarrow i\partial_{\mathbf{k}}$, one can obtain $$ \...
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89 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: ...
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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 ...
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What is the difference between a half metal (HM) and a spin gapless semiconductor (SGS)?

I would like to know what is the difference between a Half metal (HM) and a Spin Gapless Semiconductor (SGS) in terms of definition and DOS/Bandstructure appearance.
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Interpretation of effmass module

Currently, I am trying to figure out the effmass module. I'm newly into effective mass stuff and I'm able to run it and generate effective masses. However, I'm facing some trouble understanding it. Is ...
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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 ...
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304 views

Does the spin polarised DFT calculation mean broken time reversal symmetry?

Recently, I have got to learn that if time-reversal symmetry and inversion symmetry are present simultaneously in the system we have the following conditions on energy of Bloch's states: $$E_{n,\chi }(...
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How to generate the high symmetry paths for band structure calculations?

Suppose I want to calculate the band structure of a material system along a specific high symmetry path in the Brillouin Zone. If the point group of the system is given, how can I easily compute the ...
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Quantum confinement of transition metal dichalcogenides (TMDs)

TMDs (transition metal dichalcogenides) are materials that can have a layered structure. When moving from bulk to monolayers, the bandgap changes from indirect to direct according to the image (DFT to ...
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Band Curvature looks like straight lines for (221) MoS2 Monolayer in Quantum ESPRESSO

In the band structure of (221) $\ce{MoS2}$ supercell, all the curvature are looking like straight lines. I cannot calculate band gap. ...
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Predict the density of states (DOS) diagram for rhenium oxide (ReO3) from the molecular orbital diagram

Yesterday I made this query on Chemistry Stack Exchange, and a user has felt that perhaps here I will get a quicker answer. The structure of rhenium(VI) oxide, $\ce{ReO3}$, is similar to that of ...
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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 ...
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VASP GW+SOC band structure calculations

How may I carry out GW+SOC a band structure calculation using VASP? Could anyone familiar describe it step-by-step? I could not find any info regarding this on the VASP wiki.
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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?
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What is the electrical behavior of the material with this band gap?

Presently I am doing DFT calculations to analyse the electronic structure of a material. I got the band structure as shown in the figure. I would like to know the electrical behavior of this material. ...
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502 views

How to create a 3D band structure from DFT band structure calculation?

How can I create such a 3D plot using matplotlib? Like the one in Figure (a) below: I want to create it using DFT bandstructure calculation result
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What are some types of topologically-relevant band degeneracies in contemporary 2D condensed matter research?

Cross-posted on Physics.SE. In the study of 2D condensed matter systems, I have seen several kinds of band degeneracies. I call 'bands' the eigenvalues to the time-independent Schrodinger equation, ...
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Band unfolding for magnetic systems

I'm trying to study the electronic structure of a 1D antiferromagnetic (in which the spin is associated with copper atoms) via spin-polarized calculations. The unit cell dimensions are provided below (...
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218 views

How to calculate the band structure of a protein molecule

I want to calculate the band structure of a protein molecule. How can I do it using Siesta of Gaussian? I am thinking about QE/VASP as the number of atoms are 600 and computationally it is not ...
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Construct a parity operator at a TRIM point?

I want to calculate the band parity at some TRIM (time-reversal invariant momentum) point in Brillouin zone. Parity was defined as the eigenvalue of the inversion operator. My question is how to ...
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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 ...
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142 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 ...
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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 ...
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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 ...
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362 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 ...
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138 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 ...
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1answer
117 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 ...
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220 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 ...
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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?
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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 ...
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49 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 ...
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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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A doubt about extended dislocation [closed]

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 ...
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Band structure has unusual lines in the valence band using Quantum ESPRESSO [closed]

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 ...
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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, ...
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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 ...
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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 ?...
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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 ...
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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 ...
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1answer
167 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 ...
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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 ...
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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 ...
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151 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 ...
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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 ...
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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 ...