Questions tagged [condensed-matter]
For all matters related to condensed matter physics.
119
questions
3
votes
0
answers
29
views
Where can I read about Valleytronics?
Where can I read about Valleytronics? Are there any good books or review papers or influential papers on this topic?
The question was also posted at the Physics site.
2
votes
0
answers
32
views
Plane wave expansion of the wavefunction for periodic material modelling
The aim is to do an electronic calculation with static nucleus with Plane wave (PW) basis functions for an infinite periodic material. The number of functions is given by the pairs of reciprocal ...
- 723
3
votes
1
answer
46
views
How to read UPF pseudopotential for ultrasoft pseudopotential simple in a fortran program
I'm currently working on calculating semiempirical local and nonlocal matrix elements for Ga. To proceed with my calculations, I need to extract specific parameters from the UPF (Unified ...
- 371
4
votes
0
answers
42
views
Strongly Correlated Materials: Theoretical Frameworks, Computational Techniques, and Machine Learning Breakthroughs in Matter Modeling
This is more of an opened discussion, recommendations, and experts views on the Strongly correlated materials.
Exploring the behavior of strongly correlated materials poses significant challenges in ...
- 849
3
votes
0
answers
25
views
Convex hull calculations with WIEN2k
How does one do the calculation of a convex hull with the WIEN2k code for the formation energy of alloys?
- 31
4
votes
0
answers
39
views
Gauge constraint in the definition of the Z2 invariant
Cross-posted at Physics.SE.
In Fu and Kane's paper from 2006, the authors define the $\mathbb{Z}_2$ invariant for time-reversal invariant topological insulators as an obstruction to Stoke's theorem,
$$...
- 141
4
votes
0
answers
55
views
How can I improve the visualization of a band structure plot for a dense supercell?
I computed the band structure of my material's supercell using Quantum ESPRESSO,but the resulting plot appears to be densely populated with bands, like in the picture bellow:
Could someone provide ...
- 1,957
2
votes
0
answers
67
views
Why the total energy calculated with GGA and metaGGA=SCAN are so different?
Why the total energy calculated with GGA and metaGGA=SCAN are so different?
My INNCAR file is
...
- 21
1
vote
0
answers
52
views
Problem with CP2K running AIMD
I have met serious problem with cp2k running AIMD. I complied CP2K 2023.1 with gcc.9.3.0 and intelmpi. First, I ran the test1.inp file (https://1drv.ms/u/s!AtO91yh6_pLhg51bJVuIJt7N4ZZU7w?e=YtB3ZC) and ...
- 405
4
votes
0
answers
46
views
Why, if the potential is different from the Coulomb one, but has spherical symmetry, the eigenvalues of the system are non-degenerate? [closed]
Question duplicated from here https://mathematica.stackexchange.com/questions/287433/why-if-the-potential-is-different-from-the-coulomb-one-but-has-spherical-symme and here https://physics....
- 233
2
votes
0
answers
32
views
Doping induced overall bandgap narrowing vs. bandgap narrowing achieved by localized doping induced level
Doping is an efficient strategy to narrow the bandgap of wide-bandgap metal oxides, in order to harvest more light. Let's consider the mechanism by which doping reduces the bandgap of a metal oxide ...
- 167
3
votes
0
answers
140
views
Noncollinear band structure calculation with VASP
I am trying to do a band structure calculation of a noncollinear magnetic system. I am getting results that are nowhere close to what I'm expecting. I need help checking if I am following the right ...
3
votes
0
answers
144
views
Help with Mathematica for optimizing a Gaussian basis set for a hydrogen atom in a magnetic field
This is a follow-up to my previous question: Optimal Gaussian basis set for hydrogen atom in magnetic field
Brief description of the problem
I would like to find the ground and excited states of the ...
- 233
7
votes
2
answers
191
views
How to get the directives of a slurm for my Quantum ESPRESSO calculations?
Context
I saw some examples of SLURM scripts on the internet like the one below:
...
- 1,957
4
votes
1
answer
529
views
How to restart an interrupted Quantum ESPRESSO calculation?
I was doing a vc-relax calculation and after 1 day the calculation suddenly stopped. Is there a way to restart it from previous interrupted calculation of do I have to restart from the beginning?
- 1,957
5
votes
1
answer
82
views
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?
- 103
5
votes
1
answer
194
views
Geometry optimization: nuclear coordinates vs lattice parameters
I would like to know whether, at least in principle, minimization of energy with respect to nuclear coordinates leads to the same result as minimization of cell energy with respect to lattice ...
- 103
6
votes
1
answer
145
views
Optimal Gaussian basis set for hydrogen atom in magnetic field
Copy from here https://mathematica.stackexchange.com/questions/285044/optimal-basis-set-of-gaussian-functions-for-describing-a-quantum-system
This question arose during the discussion of the previous ...
- 233
5
votes
0
answers
53
views
Presence/absence of topologically protected edge states on the boundary of two topological insulators [closed]
A normal insulator is the same as vacuum because one can change the band structure from one to another without closing the gap, but for topological insulators (talking about 2D TI) like 1T'-TMDs or ...
- 51
3
votes
1
answer
88
views
Why my values of dielectric function don't match litterature (For Yambo with Quantum ESPRESSO)?
I try to reproduce the dielectric function as the picture bellow using Yambo code but the values that I have found in y-axis are so much bigger [-1000,1500] compared to literature. I generated the scf ...
- 1,957
3
votes
0
answers
61
views
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-...
- 395
5
votes
2
answers
1k
views
How to increase the number of CPUs in my computer?
I'm running my calculations using Quantum ESPRESSO on a 10th generation i7 computer (Dell) with Ubuntu.
When I run any calculation using the command ...
- 1,957
6
votes
0
answers
48
views
Is it possible to evaluate rotational and vibrational partition functions for diffusion in the Eyring Theory of Absolute Rates?
Let us consider the usual expression for Diffusion processes and diffusion coefficients in the Eyring's theory:
$$D=\lambda^2k = \lambda^2 \frac{k_BT}{h}\frac{\Omega_\ddagger}{\Omega}e^{-\frac{\...
3
votes
0
answers
38
views
Original reference for gapped chiral fermion k·p model?
In eq. 1 of this reference, the authors present the following Hamiltonian for the 2-band gapped chiral fermion model that can describe many systems including various semiconductors, N-layer graphene, ...
- 2,281
8
votes
1
answer
427
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 ...
- 297
4
votes
0
answers
115
views
If the system respects time-reversal symmetry, does the T-even anti-symmetric conductivity tensor indicate a dissipationless transport?
In this paper, the authors discuss the three response relations or Ohm's law for spin/charge transport. The first one is the spin Hall effect described by:
$$J_j^i=\sigma_{s}\epsilon_{ijk}E_k \tag{1},$...
- 14.9k
3
votes
1
answer
86
views
Symmetry for the low-energy effective model of Weyl semimetal
The low-energy effective model for Weyl semimetals (WSM) at a single Weyl point can be written as:
$$H_{w}=\chi \vec{k} \cdot \vec{\sigma}, \tag{1} $$
where $\chi$ is the chirality index, $\vec{k}$ is ...
- 14.9k
1
vote
1
answer
68
views
Is it possible to define a property like strain to characterize the structural change?
Lets suppose that I have an atom chain like system 1 below. Now, some interaction made one atom to move out of the chain, like shown in system 2 (the moved atom remains bounded but in another position)...
- 22.3k
5
votes
1
answer
91
views
How to plot downfolded bands from DFT bands?
Once you mapped the high symmetry points from primitive cell to the super cell, you need to plot the downfolded bands.
As we know in DFT output of band structure calculation we get a set of E vs k ...
- 123
2
votes
0
answers
37
views
Is there any relation between electride and an electron localization function (ELF)?
I would like to know if there is any correlation between the ELF values with materials in the electronic phase, versus with the electride phase?
- 859
1
vote
0
answers
36
views
Invariance of magnetic susceptibility when rotating a tight-binding Hamiltonian [closed]
We know the magnetic susceptibility for a non-interacting tight-binding model has the Lindhardt form, for which I express as product of matsubara Green's functions
$$\chi^{(0)}(q,\omega)=-\beta\sum_{k,...
- 111
2
votes
0
answers
65
views
How to create the supercell to simulate a disordered solid solution?
I am trying to simulate the DOS of a disordered semiconductor (Cd0.5Zn0.5S), my plan is to get the .cif file of CdS first, and build a supercell, then I should ...
- 1,977
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 ...
- 123
4
votes
1
answer
130
views
Is there any useful application to estimating the expectation value for an Ising model without magnetic field?
In the same line of thoughts as this post, I am trying to understand better in which cases quantum computers could be useful to simulate materials under some constraints on what the quantum computer ...
8
votes
2
answers
278
views
Are there interesting applications of estimating the energy for generalizations of the Heisenberg model?
I consider that $H$ is a Hamiltonian describing a quantum system of $n$ spin-1/2 particles (or qubits). I assume it can be written as (the $\alpha_k^i$ are real coefficients):
$$\tag{1}H=\sum_{i=1}^3 ...
5
votes
2
answers
145
views
What's the completeness relation of Bloch band?
Bloch's theorem can be stated as:
$$
|\Psi_{n\vec{k}}\rangle=e^{i\vec{k}\cdot\vec{r}}|u_{n\vec{k}}(\vec{r})\rangle \tag{1}
$$
where $|\Psi_{n\vec{k}}\rangle$ is the solution of single electron ...
- 14.9k
5
votes
0
answers
147
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....
- 2,793
5
votes
0
answers
50
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-...
user5405
14
votes
1
answer
242
views
What are differences between Mott and Anderson transitions?
Can anyone please explain the differences between Anderson and Mott insulator-metal transition? I found some information in the book named "The_Physics_of_Amorphous_Solids".
- 2,025
4
votes
1
answer
232
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 ...
- 123
6
votes
0
answers
466
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-...
- 161
1
vote
0
answers
47
views
What prevents us from designing material or catalysts to meet the custom requirements? [closed]
From the perspective of physics, everything is made of atoms, ions, electrons, etc. Since we know the basic interaction between elementary particles, it might be possible to design customized ...
- 1,977
8
votes
1
answer
309
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 ...
- 2,603
3
votes
0
answers
107
views
Why is there a deviation between the experimentally calculated values and theoretical done by DFT calculation? [duplicate]
If there was a deviation between the experimentally calculated values and theoretical determination done by DFT calculation, then what is the reason?
- 717
6
votes
1
answer
133
views
About LaCrO3 space group stability
I found two space groups of $\ce{LaCrO3}$ material Pnma and Pm-3m. If someone is familiar with this material, please help to understand which phase is more stable. what are the factors that determine ...
- 643
11
votes
2
answers
950
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 ...
- 1,977
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 ...
- 1,977
8
votes
1
answer
233
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\...
- 2,281
11
votes
3
answers
335
views
How does a beginner condensed matter theorist working on real materials, get up to speed?
I asked this on Physics.SE and got recommended here.
More precisely, as a condensed matter theory PhD student, I am often overwhelmed by the wide variety of chemical formulas that experimentalists ...
- 211
9
votes
1
answer
455
views
What software can I use for gas adsorption calculations?
We are from a new research group working on matter modelling. Currently our work has focused mainly on classical Molecular Dynamics (MD), Lattice Dynamics (LD) and ab-initio methods. For these, we ...
- 2,603