Unanswered Questions
314 questions with no upvoted or accepted answers
14
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Handling multiple self-consistent solutions with DFT+U
It is well-established that within the DFT+U framework, one can achieve several self-consistent solutions with greatly varying energies for the same exact magnetic ordering. In 2010, Meredig et al. ...
14
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0
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260
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Orbital magnetization in periodic solids
The orbital magnetization in periodic solids has been nicely described by the so-called modern theory of magnetization [1,2,3,4].
$$\tag{1}
\mathcal{M}_{orb} = -\frac{1}{2} \Im \sum_{n,\mathbf{k}} f_{...
13
votes
0
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379
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Calculating Core-Level Binding Energies (XPS) using DFT
I'm pretty new to DFT calculations but I'm trying to learn how to do X-ray photoelectron spectroscopy (XPS) calculations, particularly for open-shell molecular systems in common non-periodic DFT codes....
9
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248
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Different Results obtained while doing multiple runs from same inputs in VASP
I have been trying to optimize the parallelization parameters in VASP. By varying the parameters(such as KPAR and NCORE) I am trying to reduce the Elapsed time that is printed at the end of each line. ...
- 1,701
9
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184
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How to do parity analysis of band extrema?
To check whether electronic transitions are allowed between valence band maximum (VBM) and conduction band minimum (CBM) as per Laporte's rule, the parity of VBM/CBM is needed to be known. This paper ...
- 939
8
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89
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How to use the HNC approximation to find the change in grand potential
I am reading Hansen and MacDonald's Theory of Simple Liquids, and I am going through Integral Equation theories.
In section 4.3, they put forward the equation (4.3.14),
$${\small \Omega _{\phi} = \...
- 15.9k
7
votes
0
answers
108
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In DFT codes, which energy is forces derivatives of?
There was a discussion in our research group recently, that I did not follow completely, but the crux was:
In most DFT codes (especially VASP), when we compute the forces, which energy are the forces ...
- 615
7
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157
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Correct method for structure optimization using DFT tools
Lets's say I want to start off DFT calculations for a material whose experimental cell constants are known. So I have two ways to get the correct structure to later on calculate, say, band structure ...
- 939
7
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0
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95
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Degenerate local-orbital radial functions
I am trying to do a simple groundstate calculation with the exciting code for a perovskite structure with 4d-electron elements. The code uses a muffin-tin approach and expands the wavefunctions inside ...
- 330
7
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174
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Is there a way to set the spin multiplicity in a VASP calculation?
I will greatly appreciate if someone can point to whether I can specify the spin multiplicity of a vasp calculation?
I am trying to get the potential energy mapping of a system with neutral slab and a ...
- 551
7
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161
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Calculation of charge transport with the non-orthogonal basis Hamiltonian based on the non-equilibrium Green's function method
I am thinking about one question. If the Hamiltonian matrix is based on the non-orthogonal basis, how to compute the charge conductance with the Non-Equilibrium Green's Function (NEGF) method.
Suppose ...
7
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0
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167
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Scaling and speed-up of real-space DFT calculations using finite elements approach
I have recently encountered this paper in which the authors have formulated Kohn-Sham equations using the finite elements package deal.II, leading to an open-source software called DFT-FE.
It stated ...
6
votes
0
answers
116
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Spin-orbit coupling(SOC) in geometry optimisation
When I tried including SOC during the optimization of InBi lattice constants, the lattice constant increased from 4.6 Å (without SOC) to more than 6 Å (with SOC), which seems like an 'incorrect' ...
- 65
6
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62
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Examples of high sensitivity of observable behavior to the choice of DFT functional
Most computational materials science studies perform or reference some sort of baseline process for choosing the DFT functional that they will employ to model their system. It is unlikely that a ...
- 1,658
6
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0
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125
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Why are some pseudopotentials not readable in Quantum Espresso?
I am using the pseudopotentials generated using "atomic" code by A. Dal Corso after downloading the pslibrary.0.3.1. ...
- 20.1k