Questions tagged [band-structure]
Questions about the band structure of solids. Band theory forms the foundation of the understanding of all solid-state devices.
152
questions
1
vote
0
answers
29
views
How to determine high-symmetry points in case of PBE0 using Quantum ESPRESSO?
Normally when we use PBE-GGA as an approximation we can determine the high symmetry points in x coordinate from the output file of bands.x calculation . But in the ...
- 727
5
votes
1
answer
103
views
Extracting band structure data using Boltztrap for Quantum ESPRESSO
I used PBE0 in my calculations using Quantum ESPRESSO . I have ran a scf calculation then I used Boltztrap by running the command btp2 -vv interpolate -m 3 ./ then <...
- 727
2
votes
0
answers
28
views
How to add the scissor operator in Quantum ESPRESSO input?
I want to calculate the optical, transport and electronic properties of my material. GGA underestimate the bandgap.
I tried GGA+U but the bandgap is still underestimated and also when I tried to use ...
- 727
3
votes
0
answers
14
views
Issue with getting pw_bands output file for ws2
After running the input pw_bands.in file execution is not stopping even after 10hrs , and the output is not updating anything further after 1 min of the output.
- 31
5
votes
1
answer
38
views
How to add a break into CASTEP k-point path
I am trying to produce a band structure for TiO2, with the cell file shown below:
...
- 121
4
votes
1
answer
107
views
What is the number of bands in GPAW?
Silicon has 6 conduction bands of interest. In GPAW tutorials for the calculation of properties of silicon, the parameters nbands which is referred as the "...
- 332
3
votes
1
answer
37
views
Why can graphene nanoribbons be safely used as electrdes, despite having a finite band gap?
I was following the following this tutorial.
As far as my understanding goes, one should use bulk-like metallic electrodes to avoid problems with screening and Fermi-level definition.
Can someone ...
- 609
6
votes
1
answer
48
views
Confusion regarding specifying a k-point path for phonon dispersions/bandstructure plots
I have been trying to obtain a plot of the phonon dispersion of a BCC metal using Quantum Espresso. In the literature it seems that a commonly reported path is ...
- 111
3
votes
0
answers
19
views
Do I have to repeat my previous calculations after increasing 'diago_david_ndir' in the input file of the bandstructure calculations?
After doing the convergence test, 'vc-relax' and 'scf' calculations for my material using Quantum ESPRESSO everything went well. But when I wanted to do a 'bands' calculation for bandstructure I got ...
- 727
3
votes
1
answer
43
views
Adjusting y-axis of CASTEP band structure plots
when I produce a band structure plot using XMGRACE after running a CASTEP Bandstructure calculation I would like to have the bottom of the band gap to be zeroed. Is there an easy way to shift the axis,...
- 121
4
votes
0
answers
59
views
Electron-phonon coupling plotted as function of phonon bands
I'm looking to superimpose electron phonon coupling (EPC) constants per phonon band per k-point as is done in Figures 6c and 6d in this paper, essentially a "fat band" plot where the ...
user4763
3
votes
1
answer
96
views
PyProcar band-structure plot error
I am getting the following error when trying to plot band-structure using PyProcar. I posted a comment in author's github page as well (see at the bottom). In the meantime, I wonder if anyone could ...
- 161
4
votes
1
answer
50
views
CASTEP Spectral Bandstructure Tasks
I am struggling to find an explanation for the difference between a spectral band structure task and a normal band structure task. I have attached example .param files. Also, does the BS_XC_FUNCTIONAL ...
- 121
1
vote
0
answers
37
views
VASP: HS06 hybrid functional bandstructure with downsampled fock operator
I am using vasp 6.2.0 to calculate bandstructure with HS06 hybrid functional. I have done
a DFT self-consistent calculation with GGA functional, on a uniform 20x20x20 grid; from this I copied the ...
4
votes
0
answers
76
views
VASPKIT usage for Band structure calculation for HSE06 calculation
I was calculating the Band structure for HSE06 Functional using VASPKIT as has been described here. But some seniors of mine told me that this method is not reliable in order to calculate the Band ...
- 629
2
votes
0
answers
26
views
What is a lattice regularization scheme?
I am trying to read this paper
Chiral Anomaly from Strain-Induced Gauge Fields in Dirac and Weyl Semimetals
https://journals.aps.org/prx/abstract/10.1103/PhysRevX.6.041021
In section II the authors ...
- 121
6
votes
2
answers
91
views
Optical Band gap determination from absorption coeffecient using DFT
I am currently working with a perovskite material which shows forbidden transitions. Older studies used bigger values of $\alpha$ in HSE06 calcualtions(to match with experimental Band Gap) but a ...
- 629
3
votes
1
answer
83
views
How to carry out Spin-projected band structure calculation( as shown in figure)using VASP?
How to carry out Spin-projected band structure calculation( as shown in figure)using VASP?
I couldn't find any good source for this kind of plotting, is there a code for this kind of plotting other ...
- 547
11
votes
1
answer
346
views
Software recommendations to construct band structures using tight binding
I am at the beginning of computational materials modeling.
My objective is to calculate the electrical conductivity of a system that consists of several thousand atoms, and running DFT calculations is ...
- 113
10
votes
1
answer
311
views
Should one perform geometry optimisation before calculating electronic/phonon band structures via DFT?
I am new to DFT calculations and I would like to get the electronic and phonon band structures of FeSn (1 kagome layer and 1 Sn layer in between). My question is, is it absolutely necessary to first ...
- 101
5
votes
0
answers
123
views
Standard Practice for Relaxation, Band Structure and Density of States Calculations wrt smearing method
My question is mainly one about consistency in the smearing method used for a standard "geometry relaxation + band structure (BS) + density of states (DOS)" set of calculations. This is a ...
- 687
1
vote
0
answers
29
views
How Can I Create a 2D Silicon Carbide Structure using VESTA
I'm just getting started with VESTA. SO I'm fairly new to it. Can anyone suggest me how to build a 2D structure of Silicon Carbide (SiC)? Or any documentation would also help.
Thanks .
- 19
3
votes
0
answers
60
views
Zig zag straight lines bands from Quantum Espresso calculations
During band structure calculations in Quantum espresso I found that the bands are coming in Linear form and not curvature. Why is this happening? Is there any explanation for this? Which parameters ...
- 1,015
2
votes
1
answer
67
views
How to increase high symmetry points in band structure?
Can I repeat high symmetry points manually by copying the sequence on input file?
5
votes
1
answer
158
views
How to find which atoms/bonds contribute to the particular section of band structure?
In this paper, in the first sentence of page no.6723, the authors attribute a particular section of band structure (in momentum space) to the bonds/ atoms in real space. I would like to know methods ...
- 315
4
votes
1
answer
108
views
3D band structure plot
I am trying to plot 3D band structure of my system of interest. I have used Quantum Espresso software for calculating the band structure and plotted 2D band diagram. But from here I am unable to ...
- 61
5
votes
0
answers
60
views
About the mechanism of opening of the band gap in topological insulator with the inclusion of SOC [closed]
When we work on the topological insulator (protected by time reversal symmetry ), it is often said that the SOC is the main ingredient because it is a way to open a gap when the band inversion present....
- 2,763
4
votes
0
answers
57
views
Extracting hopping parameters for band structure calculations from Atomic coordinates
I have relaxed atomic coordinates of bilayer graphene obtained from LAMMPS MD simulations.
I want to extract hopping parameters (tight binding model or continuum model) to obtain the band structure of ...
- 81
6
votes
1
answer
284
views
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,...
- 1,915
11
votes
2
answers
280
views
Temperature Effect on Band gap in solid state calculation
I am new in solid-state calculation field.
There has been pretty well-known to use DFT or DFT+U method to calculate the electronic properties such as the band gap for metal, and semiconductors.
When I ...
- 241
5
votes
1
answer
94
views
Cross-post: Matrix elements <n,k|x|n',k'> for Bloch states
Cross posted at Physics.SE
I believe this is just elementary QM, but I'm getting awfully confused. The question is drawn from this paper on Wannier-Stark localization (but is self-contained).
Let:
\...
- 51
3
votes
1
answer
171
views
What does it mean if the Fermi level crosses into the valence band? How about into the conduction band?
Just recently got into DFT and I've been doing a few calculations on my own on Quantum Espresso. I've come up with electronic band structures for materials that I've been looking at and I was hoping ...
- 171
4
votes
1
answer
383
views
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
1
vote
1
answer
492
views
Repeated error in Quantum Espresso "Error in routine potinit (1)"
I have been trying to perform some calculations in Quantum espresso on mono-layer Borophene. Initially, I have optimized the structure which succeeds. Subsequently, I am trying to use this optimized ...
- 69
9
votes
1
answer
199
views
Different band structure in supercell, but not due to band folding
This is my first time asking a question - if I mess something up please let me know and I'll amend. I believe this goes beyond questions on how to use QE so here seems appropriate over the QE forums.
...
- 131
22
votes
2
answers
334
views
Easy ways to generate "teaching" band structures in Python?
I'd like to introduce band structure to a class of undergraduate chemists, along the lines of Roald Hoffmann's Solids and Surfaces.
That is, I'd like to start with a s-band in 1D, which is easy ...
- 8,225
9
votes
2
answers
562
views
How is the right k-path chosen for band structure?
When generating the kpoint by vaspkit for two compounds that have the same lattice system, I found the kpath is
G–X–S–Y–G–Z–U–R–T–Z|Y–T|U–X|S–R.
But why in the article (as shown in the picture) was a ...
- 547
9
votes
2
answers
331
views
Why do we need to use fake k-points when doing HSE band structure in VASP?
I want to know why we need fake k-points in HSE band structure calculation? I mean why we can't take a simple high symmetric path like we do in PBE calculation?
4
votes
0
answers
128
views
The comparison of bandgap value of slab and bulk phase [closed]
I tried to calculate the bandgap of the TiO2-Rutile bulk phase, DFT(not +U) calculation shows the bandgap is about 1.8eV, which is roughly the same as the 1.78eV on the Material Project. When ...
- 1,915
2
votes
0
answers
57
views
How would surface state affect the band gap value of semiconductors? [closed]
I am struggling to figure out the relationship between bandgap value and surface states. To my understanding, when considering the material that includes surface, there would be some surface states in ...
- 1,915
6
votes
1
answer
215
views
What parameters should be checked on both unit cell and super cell to make sure the calculations are going fine?
Question is based on further learning about the previously asked question - Do NSCF calculations on Supercell gives different band gap than the Unit Cell?
How should I compare SCF and NSCF ...
- 1,015
8
votes
1
answer
173
views
Do NSCF calculations on Supercell gives different band gap than the Unit Cell?
NSCF (non-self-consistent field) calculations are done on a dense mesh. I did it on a unit cell. Then since I have to try using a supercell for alloying, I am doing calculations to see the results of ...
- 1,015
11
votes
2
answers
699
views
Why the band structure of a slab is not smooth?
I am trying to calculate the band structure of a TiO2-Rutile slab, but the result I got is not very smooth, and the result shows it is an indirect gap material, but the bulk phase of TiO2-Rutile is a ...
- 1,915
6
votes
1
answer
221
views
Is it necessary to do self-consistent calculation after structure optimization?
When calculating the band structure of a material, I have been told that at first, I need to do structure optimization to get a stationary structure(1st step), and then keep the atoms' position fixed, ...
- 1,915
6
votes
0
answers
338
views
How to interpret density of states and band structure of a material? [closed]
I am new on the VASP platform, and have learned how to calculate any material's DOS and Band structure.
However, I don't know how to interpret these properties. Can you recommend resources that ...
- 519
8
votes
1
answer
138
views
Which software is suitable for visualizing the electron wavefunctions in a crystal?
I'd like to use the tight-binding model with a linear combination of atomic orbitals.
It should show the full energy bands, as well as the spatial probability distribution for each eigenfunction of ...
9
votes
1
answer
153
views
How to identify localized surface states in the band structure
After calculating the band diagram of a structure, is there a way to identify localized surface states?
I am working with Si nanowires with different cross sections. I want to determine the band gap ...
- 2,583
6
votes
1
answer
361
views
SC vs NSC Fermi energy in VASP, which is correct?
While calculating the band structure using VASP, we usually take two steps: one is the self-consistent run to get the right CHGCAR file; and the other is a nonself-consistent calculation to generate ...
- 101
5
votes
1
answer
104
views
Tool to saturate the dangling bonds at the surface of nanostructures
When it comes to studying 2D, 1D or 0D nanomaterials, saturating the dangling bonds in the surface helps remove unwanted localized surface states from the band structure 1. However, so far I have not ...
- 2,583
8
votes
1
answer
183
views
How to change the magnetization direction in Quantum ESPRESSO?
I have a magnetic crystal system. I want to calculate the total energy of the system if the magnetization direction is aligned in different directions such as [110], [010]. By default Quantum ESPRESSO ...
- 2,481