Questions tagged [solid-state-physics]

Questions about solid state physics.

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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/tarball anywhere. Can someone kindly share any ...
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6 votes
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How to get a Wannier function for a tight-binding model numerically?

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-...
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9 votes
1 answer
155 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 ...
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3 votes
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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!
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9 votes
1 answer
85 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),...
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6 votes
1 answer
69 views

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

$\ce{TiCoSb}$ has Wyckoff position as ...
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8 votes
2 answers
214 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 ...
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11 votes
2 answers
503 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 ...
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4 votes
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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 ...
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7 votes
1 answer
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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\...
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8 votes
1 answer
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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 ...
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6 votes
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74 views

How to define ferrimagnetism in Quantum ESPRESSO

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 ...
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9 votes
1 answer
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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 ...
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6 votes
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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 ...
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11 votes
1 answer
178 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 $$ \...
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8 votes
0 answers
63 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 ...
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12 votes
2 answers
88 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 ...
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17 votes
4 answers
430 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 ...
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11 votes
1 answer
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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 ...
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8 votes
0 answers
95 views

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

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 ...
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6 votes
1 answer
61 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 ...
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9 votes
1 answer
98 views

Can I have a bond formed for only one spin?

I'm making a topological analysis of a nanotube interacting with some metals. The steps for the calculations were: Optimizing the geometry (I am using SIESTA code). Obtain the electronic density for ...
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11 votes
1 answer
128 views

Methods to determine the vacuum level in 2D compounds in the presence of dipoles

When 2D compounds have a dipole, the potential distribution becomes linear (the left panel of the figure). After considering the dipole correction, the potential has two plateau regions in the vacuum (...
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5 votes
0 answers
171 views

Why does numerical computation of Berry curvature give me a correct Berry phase when it is supposed to diverge?

I implemented the standard numerical algorithm for calculating the Berry curvature in MATLAB. For a given 2D system, I can visualize the Berry curvature over parameter space. If I sum the Berry ...
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5 votes
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42 views

What's the difference between dynamic and static strain aging? [closed]

I do understand how static strain aging occurs and why the yield point comes back if ample time is allotted after a loading and unloading cycles primarily due to diffusion of substitutional and ...
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8 votes
2 answers
332 views

What will break the time-reversal symmetry?

Specifically, I am interested in the time-reversal symmetry $(\mathcal{T})$ in quantum mechanics. The $\mathcal{T}$ is considered as an anti-unitary operator, namely: $$\mathcal{T}\psi(\vec{r},t)=\psi^...
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5 votes
1 answer
69 views

elastic constants transformation/basis change P21/a -> P21/n

I just calculated the stiffness tensor for a given material (a monoclinic molecular crystal) using molecular simulation. When trying to compare my results to published experimental results I found ...
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16 votes
12 answers
10k views

Is it better for me to study chemistry or physics?

I might decide to pursue material science. Aptitude and background I am from the UK, and for A-levels, I am studying Maths, Further Maths, Physics and Chemistry, and I am predicted decent grades in ...
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8 votes
0 answers
133 views

Can we calculate bond enthalpies for each bond in a supercell of a disordered AB crystal using DFT? [closed]

Apart from using Bader charge analysis or energy of formation estimation, I wonder if there is a way to compute the bond energy of constituent bonds in a crystal using density functional theory. Let's ...
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9 votes
1 answer
2k views

What is the physical meaning of occupations='smearing' in Quantum ESPRESSO?

I want to understand, what is the intuition behind using the occupations='smearing' or 'tetrahedra' in Quantum ESPRESSO input file? I mean how we can interpret what is going to happen inside of ...
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8 votes
2 answers
76 views

Combined effects of strain and doping on the electronic structure of semiconductors

I've read papers in DFT studies on band gap tuning in semiconductors and the usually studied methods are either through doping or application of external strain. But it is always just one or the other....
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10 votes
1 answer
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How to understand the crystal field splitting of d-orbitals in a trigonal prismatic geometry?

This question is coming from this paper, which investigated the spontaneous spin and valley polarizations of monolayer LaBr2. The geometric information of monolayer LaBr2 is displayed as following (Br:...
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10 votes
2 answers
331 views

Morse potential for phonons in solids instead of the harmonic potential approximation?

As the title says, the Morse potential (https://en.wikipedia.org/wiki/Morse_potential) is an exactly solvable model in quantum mechanics, just like the quantum harmonic oscillator. Extensions of it ...
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8 votes
1 answer
507 views

How to perform virtual crystal approximation calculations in VASP?

Can someone share appropriate tags and methods to perform virtual crystal approximation calculations in VASP?
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8 votes
1 answer
195 views

How to calculate the orthogonal representation of a HCP cell?

I'm trying to write a program to calculate the neighbor lists of crystal systems. I found a few codes that are able to calculate it for orthogonal systems. How can I do it for non-orthogonal cells ? ...
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10 votes
0 answers
76 views

What are the methods of modeling Jahn-Teller effects in a solid-state material? [closed]

The Jahn-Teller effect arises from the symmetry breaking (distortion) of the local environment for the crystal field of 3d transitional metal ions.The distortion result in energy saving of electronic ...
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9 votes
0 answers
125 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 ...
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6 votes
1 answer
93 views

Charge density wave and band inversion

Is there any connection between charge density wave and band inversion? Or is there any system in which band inversion follows the same mechanism as the CDW? I am just trying to find a connection ...
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15 votes
0 answers
203 views

Why does the Wolff algorithm slow down in a 4-body Ising model?

In the paper that introduced "Self-learning MC" (an ML-inspired MC technique, as I understand) the authors consider a many-body Ising model as an example to show the efficiency of their ...
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12 votes
1 answer
203 views

Ising models with many-body interactions

I find it surprisingly difficult to find researches/papers on systematic "many-body interaction" extensions of the Ising model. Can somebody tell me a good review/article etc on this matter ...
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15 votes
5 answers
539 views

What are some open-source all-electron DFT alternatives to Wien2K?

Since the beginning of the century, Wien2K has proven to be a very powerful player in computational condensed matter and materials physics. Wien2K is an all-electron periodic DFT code based on the ...
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13 votes
1 answer
2k views

Labeling of high symmetry points in Brillouin zone

A Brillouin zone is defined as a Wigner~Secitz primitive cell in the reciprocal lattice [1,2]. The construction of the first Brillouin zone for two different 2D lattices are shown below: The ...
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20 votes
1 answer
149 views

What class of materials are closest to realizing the tunable coupling Hamiltonian?

From a physics point of view, there is an effective (approximation to second-order coupling Jaynes-Cummings) Hamiltonian of the form [1] \begin{equation} H=\sum_j\omega_j(t)\sigma_j^z+\sum_{\langle i,...
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