Questions tagged [solid-state-physics]

Questions about solid state physics.

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How did they calculate the indirect radiative recombination rate in this paper?

In this paper they calculated radiative recombination rates for Germanium using an effective mass model and I am trying to calculate the indirect spontaneous radiative recombination rate related to ...
Peter Pien's user avatar
2 votes
0 answers
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Temperature effect on electronic properties

I'm particularly interested in studying how temperature affects electronic properties. However, I've been working with Quantum Espresso and its DFT + U functionality, and I'm struggling to understand ...
Prasad's user avatar
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Symmetries and Permutation in the Slater-Koster matrix elements

In Wikipedia there is a list of Slater-Koster matrix elements, but not all of them are listed because "matrix elements that are not listed in this table can be constructed by permutation of ...
Qwertuy's user avatar
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Compare transition matrix elements in molecules and solids

Is there a general trend such that transition matrix elements for electronic/excitonic transitions are larger/smaller in molecules than in inorganic solids or vice versa?
freude's user avatar
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1 answer
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What is the Herman-Skillman method?

In the paper Norm-Conserving Pseudopotentials (1979), they refer to the authors' book for the all-electron(AE) calculation: ...
mle's user avatar
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Can the electron charge density of two material systems be similar?

Broadly given two electron charge density (ECD) fields, is it possible to distinguish between the elements present in both the systems? Since the ECD does not explicitly present any information on the ...
Pranoy Ray's user avatar
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7 votes
1 answer
121 views

In solids physics, how are Van Der Waals forces modelled?

I'd like to know how to treat VdW interactions among layers. Specifically I'm using Quantum Espresso and I'd like to know how VdW forces are implemented in the Kohn-Sham equation. Does it insert a $V \...
CoolerThanACooler's user avatar
6 votes
1 answer
218 views

Negative band gap in DFT calculations

I am performing DFT simulation (with Quantum Espresso) for a large number of crystalline materials to estimate their band gap energies. I am getting negative band gap values for many of them (...
Prashant Govindarajan's user avatar
3 votes
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Hilbert transform on the Bethe Lattice

In order to compute the local Green's function on the Bethe lattice, it is necessary to perform a Hilbert transform $$G_{loc}(\omega) = \int \frac{DOS(\varepsilon)}{\omega-\varepsilon} \text{d}\...
NehZio's user avatar
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3 answers
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The "Tetrahedron method does not include variations of the Fermi occupations" Problem

I am doing computation of tetragonal CsPbBr3 perovskites. When I set ISMEAR = -5 I found such a problem: This problem is absent at ISMEAR = 0. What is the cause of the problem and how do I solve it?
蕭力諶's user avatar
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1 answer
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How is magnetization of a solid obtained from electron density in a DFT framework?

What's the theory behind these kind of calculation? What are keywords and concepts I have to search for?
chemdamned's user avatar
10 votes
1 answer
579 views

Difficulty in interpreting electronic band structures in solid state physics

My background is in ab initio calculations of atoms and molecules, and I consider myself to have a good understanding of the underlying quantum theory of electronic structure and electronic spectra ...
Szgoger's user avatar
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2 votes
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Antibonding, non-bonding or bonding hybridization [closed]

In case of CsSnI3 and CsGeI3 perovskites, the strong antibonding hybridization of Sn-s/Ge-s state with I-p state lies near to VBM of these materials. In this informative paper (P.No.13853, 14th line), ...
AbPhys's user avatar
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6 votes
1 answer
678 views

Simulated STM Image with Quantum-ESPRESSO's pp.x

Context: I am an undergraduate "self-taught" noob when it comes to QE. (I've just been using online resources and textbooks thus far.) There are no QE or DFT experts at my university (I have ...
D_C's user avatar
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5 votes
1 answer
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Can specifications of a second-order phase transition of a solid be obtained with the Hartree-Fock (or DFT) calculation?

At some temperature a crystal lattice of a solid can be rearranged or to say it more precise - got new positions of its cores. This phenomenon is well-known to be called a second-order phase ...
SFriendly's user avatar
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Kohn anomaly and avoided crossing (or anticrossing/level repulsion) [closed]

Kohn Anomaly and Avoided Crossing (Anticrossing/Level Repulsion) are terms that are found to be used when discussing phonon dispersion. The former (see last paragraph, page 198) is related to electron-...
AbPhys's user avatar
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2 answers
166 views

What makes the inhomogeneous electron gas more interesting than its homogeneous counterpart?

This question is asked in the context of the famous paper on DFT by Hohenberg and Kohn. What makes the inhomogeneous electron gas more interesting than its homogeneous counterpart?
AbPhys's user avatar
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Why do we not get DOS by summing over all the PDOS?

If we sum over all the PDOS (Projected/Partial Density of States), will we have the total DOS or simply the DOS? This was not the case in my DOS and PDOS results for a simple Al atom. I am wondering ...
Abdul Muhaymin's user avatar
4 votes
1 answer
281 views

Optimzation for Large supercell

I am trying to optimize a copper supercell for the study of chalcones adsorption using Quantum ESPRESSO, however, the size of my supercell is large (>200 atoms) and QE can not handle it. What is an ...
Everson Gomes's user avatar
2 votes
0 answers
53 views

Excited state frequency for periodic systems [closed]

Is there any way to calculate the excited state frequencies of a period system using DFT?
sthomas's user avatar
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3 votes
1 answer
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I'm considering to take an introduction course with textbook "Materials Science and Engineering: An Introduction", as a beginner QE user. Is it okay?

People, I am a beginner in material modeling (I am studing solid state in Quantum ESPRESSO) and I am having a lot of difficulty with basic terms like "k-points", "Miller Indices", &...
Everson Gomes's user avatar
8 votes
1 answer
481 views

Screened Coulomb interaction and its direct Fourier transform

I have a question concerning the screened Coulomb interaction in periodic systems. Many first-principle DFT codes provide the possibility to compute linear response functions, such as the irreducible ...
franz's user avatar
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2 votes
0 answers
41 views

Can we create a phonon with a specific wavenumber that persists in the system for a long time? [closed]

The phonon number is not a conserved quantity, they add up as dictated by the dispersion relation until the Planck distribution is reached. However, I would need the k=PI/a phonons not to disappear ...
user3916292's user avatar
4 votes
2 answers
237 views

Which properties would you study to evaluate spatial confinement of a molecule

I'm modelling molecules confined within porous materials and I was wondering which molecular properties would you consider to access the confinement. Í'm thinking about looking into long-range ...
manuelpb's user avatar
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1 answer
167 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 ...
AbPhys's user avatar
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8 votes
0 answers
128 views

How to do parity analysis of band extrema?

To check whether electronic transitions are allowed between valence band maximum (VBM) and conduction band minimum (CBM) as per Laporte's rule, the parity of VBM/CBM is needed to be known. This paper ...
AbPhys's user avatar
  • 405
3 votes
2 answers
69 views

What happens to the position coordinates of the nearest neighbors in supercell studies?

Can anyone tell what happens to the position coordinates of the nearest neighbors when we choose to study supercell of the same material. That remains intact or any changes will be there? For example ...
Alpha_Roy's user avatar
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0 answers
53 views

The polarization lattice of a non-polar one dimensional chain [closed]

I have been trying to understand the concept of dielectric polarization in material science mostly by following Nicola Spaldin's lecture notes I am confused by the claim that the polarization of a non-...
user avatar
4 votes
1 answer
259 views

How to map high symmetry points from primitive cell to conventional cell?

We usually plot electronic bands with the help of high symmetry points of the irreducible zone of primitive cell of particular material. But if we want to plot bands with conventional cell, we have to ...
Alpha_Roy's user avatar
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5 votes
1 answer
206 views

How to download METADISE code?

I have a (possibly trivial) question regarding the METADISE code. I can find the documentation related to this code, but I cannot find the download page or tarball anywhere. Can someone kindly share ...
ansonthms's user avatar
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528 views

How to get a Wannier function for a tight-binding model numerically? [closed]

I have a question about construction of a Wannier function for a tight-binding model. Let's say we consider the tight-binding model of a 1D chain with two atoms (site A and B in a unit cell). In k-...
Ricky Pang's user avatar
8 votes
1 answer
326 views

Can deformation potential theory be applied to 2D and 1D systems?

I was pointed towards the use of the Deformation Potential (DP) theory to calculate the electron relaxation time in a previous question. However, I still have a doubt regarding its applicability to 2D ...
PBH's user avatar
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3 votes
0 answers
52 views

Cutoff energy in Quantum ESPRESSO calculation [duplicate]

What is cutoff energy in solid state calculations? I would just like a detailed explanation and the applicable formulas!
Paulie Bao's user avatar
  • 3,813
9 votes
1 answer
221 views

How to find the Cauchy stress tensor in solids using ab-initio methods?

I want to find the Cauchy stress tensor in certain materials with ab initio methods. I already have the analytical form of my own definition of "energy" and "forces" (not from DFT),...
Tack_Tau's user avatar
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6 votes
1 answer
304 views

What Wyckoff position to put in Input file of Unit Cell of TiCoSb?

$\ce{TiCoSb}$ has Wyckoff position as ...
epsilon02fft's user avatar
  • 1,392
8 votes
2 answers
594 views

Mobility and chemical potential

I have been studying the Boltztrap2 software to calculate the thermoelectric properties of materials. However when following the tutorial given, the Seebeck coefficient is plotted against ...
Brian Lancaster's user avatar
11 votes
2 answers
1k 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 ...
Jack's user avatar
  • 1,997
4 votes
0 answers
31 views

Do the VBM and CBM have to be on the high symmetry point? [duplicate]

I am trying to generate the band structure of a slab, a lot of tutorials tell me that I need to generate the high symmetry K point path, but I am wondering that if the VBM and CBM have to be on the ...
Jack's user avatar
  • 1,997
8 votes
1 answer
263 views

How to numerically calculate quantum state distance using quantum metric?

In Ran Cheng's review of the quantum geometric tensor, eq. (11) gives the tensor as: $$ Q_{\mu\nu}=\sum_{n\neq 0}\frac{\langle\phi_0|\partial_\mu H|\phi_n\rangle\langle\phi_n|\partial_\nu H|\phi_0\...
TribalChief's user avatar
  • 2,321
8 votes
1 answer
259 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 ...
Hans-Ulrich Rudel's user avatar
6 votes
0 answers
232 views

How to define ferrimagnetism in Quantum ESPRESSO [closed]

I would like to pick this problem from my previous post See link. I am clear about how to define antiferromagnetism in QE. Here I am with another issue. I am ...
astha's user avatar
  • 1,663
9 votes
1 answer
459 views

Why is the planewave codes ecosystem healthier on free/opensource software adoption, when compared to codes supporting atom-centered orbitals?

Regarding the branch of matter modeling that deals with electronic structure methods, I think we can divide it in two camps: Those who work mostly with planewave-based software, geared towards ...
ksousa's user avatar
  • 4,088
6 votes
0 answers
114 views

Constructing the symmetry operator from k.p Hamiltonian [closed]

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 ...
JensenPang's user avatar
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11 votes
1 answer
310 views

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 $$ \...
Xiaoming Wang's user avatar
8 votes
0 answers
100 views

Constructing an anisotropic crystal in WulffPack [closed]

I am trying to create an $\ce{LiFePO4}$ crystal in WulffPack. I have the surface energies of seven different surfaces from the paper [1]. When I input the same to WulffPack, it creates a structure ...
chatte22's user avatar
12 votes
2 answers
118 views

What are properties of interest for energy storage materials?

In the field of simulation for energy storage materials, there is always a gap between theoretical calculations and demand for experimentalists. What could be directly calculated from ab initio ...
Paulie Bao's user avatar
  • 3,813
18 votes
4 answers
707 views

Good books about computational chemistry of solid state materials for newbie

At the University, I chose the organic chemistry path and to better understand my experimental works I started studying computational chemistry on my own. There are a lot of books in this field, but I ...
NickZ's user avatar
  • 1,479
12 votes
1 answer
1k views

Increasing k-point grid to take DOS calculation

I was trying to compute some electronic properties for Pd using SIESTA and VASP for some computer practicals in my university, specially focused on band structure and density of states (DOS) using LDA ...
Paul Logan's user avatar
8 votes
0 answers
117 views

Example of a standard/archetypal/simple 4-band gapped condensed matter model with analytic results? [closed]

I am looking to study Berry phase-like phenomena in a gapped 4-band material model. In particular, I want to numerically and analytically calculate the Abelian Berry curvature integral of each band ...
TribalChief's user avatar
  • 2,321
6 votes
1 answer
71 views

Example of a standard/archetypal/simple 4-band un-gapped condensed matter model with analytic results?

I am looking to study Berry phase-like phenomena in an un-gapped material model. However, I am having trouble finding a widely-used 4-band model with analytic expressions for wavefunctions and ...
TribalChief's user avatar
  • 2,321