Unanswered Questions
53 questions with no upvoted or accepted answers
11
votes
0
answers
145
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Have FDTD methods made inroads into dynamical simulation of electron and/or X-ray scattering by crystals?
I'm afraid this question might be too basic or too naive or both, but here goes!
For optical diffraction by periodic nano-structures (gratings, semiconductor manufacturing metrology) the rigorous ...
8
votes
0
answers
96
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How do I identify an oblique surface mesh?
I have drawn three surface meshes from a hexagonal material for the $(0001)$, $(1\bar{1}00)$ and $(1\bar{1}01)$.
The first one would be the top horizontal surface of the hexagonal structure, the ...
- 15.9k
7
votes
0
answers
57
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Database (or table) of functions obeying symmetry properties of space groups
I'm looking for a table or database containing mathematical functions that belong to crystallographic space groups by having the same symmetry elements.
Imagine a 2D square planar lattice. It has a 4-...
7
votes
0
answers
448
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Straightforward formalism to get sets of lattice vectors of fcc (111), (110) and (100) facet surfaces that I can also cite?
I am simulating low energy electron diffraction (LEED) from a polyfaceted sample. Usually it's a single, well-defined flat crystalline surface.
Since low energy electrons (below a few hundred eV) only ...
- 2,074
7
votes
0
answers
201
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How to convert lab frame quaternions and plane normal to misorientation quaternion and crystal plane normal for grain boundaries?
Background
Let qA and qB represent unit, orientation quaternions of grain A and grain B of a grain boundary in the lab reference ...
- 15.9k
6
votes
0
answers
77
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Benchmarking DFT vs Experimental Gaps - Confusion over Fundamental and Optical Gaps
Recently, I've come across discussions about the differences between fundamental (or electronic) bandgaps and optical bandgaps, with the two quantities differing mainly by the electron-hole binding ...
- 1,366
5
votes
0
answers
41
views
Rich editing of ASE images
I want to produce some images related to graphene-like materials.
I was able to draw them using ASE visualize module after constructing the atomistic model. However ...
- 24.2k
5
votes
0
answers
202
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Optical properties using ESPRESSO's epsilon.x
Currently I'm using epsilon.x from Quantum ESPRESSO to analyse optical
properties of metallic alloys. I'm getting a wiggling curve for the dielectric function.
For the imaginary part of dielectric ...
- 3,394
5
votes
0
answers
396
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How can I properly plot this .cube file in Python?
Motivation for Post: I saw a question about how to plot a .cube file recently on the Mathematica & Wolfram Language Stack Exchange. It was marked "off-...
- 143
5
votes
0
answers
86
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Packages that can model effects of intense electric fields from femtosecond compressed IR and EUV laser pulses on surfaces?
Laser-based and time-resolved ARPES are relatively1 new techniques to study atomic and especially electronic structure (necessarily) near crystal surfaces and of adsorbed 2D materials on those ...
- 2,074
5
votes
0
answers
47
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How to transform a perturbed surface structure to a reference surface structure?
Say I have a bulk FCC Pt structure obtained from Materials Project with a lattice constant a = 3.94 Å. I first did DFT to relax the bulk structure, and the optimized lattice constant becomes for ...
- 1,970
5
votes
0
answers
120
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How to find the most stable facet for a crystal?
I am trying to find the most stable facet for a crystal, but since there are many possible choices, like (1 0 0),(1 1 0),(1 1 1),(2 1 0), etc. My questions is:
I am wondering how should I determine ...
4
votes
0
answers
45
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Doubt regarding Ehull (energy above convex hull) and formation energy
I am creating a ML model for predicting thermodynamic-stability of 2-d materials, for predicting stability formation energy and Ehull (Energy above convex hull) is used and this is how it is also ...
- 24.2k
4
votes
0
answers
48
views
How to calculate the volume energy loss function (VELF) using Quantum ESPRESSO?
How to calculate the volume energy loss function (VELF)?
Could you please share with a simple example (with related input files, output files and/or plot)?
Any relevant links would also be welcome.
4
votes
0
answers
65
views
Calculating excitonic optical properties with BSE level in VASP
I have been working on 2D material systems and their heterostructures. While calculating BSE excitonic optical properties in VASP, I encountered that the 2D material property is well matched with ...