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22 votes
Accepted

How to deduce phase transitions from a phonon calculation?

Background theory. In the harmonic approximation, the potential energy surface (PES) is expanded about an equilibrium point to second order, to obtain the Hamiltonian: $$ \hat{H}=\sum_{p,\alpha}-\frac{...
ProfM's user avatar
  • 11.1k
11 votes

Has materials modeling made any specific contribution to the success of perovskite solar cells, or has it only been experimental?

If you are looking for theoretical prediction of candidate perovskite solar cell materials; I have come across several papers that couple high-throughput density functional theory calculations along ...
Achintha Ihalage's user avatar
8 votes
Accepted

Perovskite formation energy from precursors

You should definitely not use the chemical potentials of the constituent elemental materials in general, since for multi-elemental compounds they are not internally consistent. As an example, Pb and I ...
Phil Hasnip's user avatar
  • 8,237
8 votes

How to calculate temperature dependent phonon band structure in VASP

There are two main contributions that can be included in the DFT context when calculating phonons at finite temperature: Thermal expansion. As temperature increases, the volume of materials changes (...
ProfM's user avatar
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7 votes

What specifically was it, that helped perovskites become so popular?

While I can't speak to the specific interest of solar cells, Perovskite is the primary ore source for Titanium. Owing to the fact that alloys of Titanium played a critical role in modernization of ...
Raz Jugovic's user avatar
7 votes

Has materials modeling made any specific contribution to the success of perovskite solar cells, or has it only been experimental?

To add to the previous answer: the new lead-free halide double perovskite $\ce{Cs_2InAgCl_6}$ was discovered by first-principles and then synthesized: G. Volonakis et al. $\ce{Cs_2InAgCl_6}$: A New ...
sponce's user avatar
  • 171
6 votes

Geometrical Optimization not converging for a double perovskite quantum dot, using Gaussian

OK, I do not want to be that guy, but I will be that guy. Some general remarks You should plan better your calculation projects. You got 129 SCF cycle calculated in about 3 days. Even if this ...
Greg's user avatar
  • 1,807
5 votes

Geometrical Optimization not converging for a double perovskite quantum dot, using Gaussian

I didn't deal with perovskite before, but I got this problem when I used metal atom in my complex. So, from my point of view, I think your calculation needs more cycles to get converged so what about ...
Abd-Elazeem Mohamed's user avatar
3 votes

How to calculate temperature dependent phonon band structure in VASP

You can try the library TDEP, which has an example to calculate Phonons dispersions as a function of temperature.
Raghunathan Ramakrishnan's user avatar
3 votes

Why I got more atoms than expected when generating POSCAR from VESTA

When you input the coordinates into VESTA, they should be the symmetrically distinct basis atoms. If you hit "Apply" after inputting only the first Cl atom, you can see that the other two Cl ...
rmza7's user avatar
  • 329
2 votes

The "Tetrahedron method does not include variations of the Fermi occupations" Problem

The issue has been resolved. It seems that it was caused by rounding the cell parameters to the sixth digit after decimal point instead of printing all 16 digits of it. (I was applying some strain and ...
蕭力諶's user avatar
  • 451
2 votes

Phonon Dispersion of SrTiO3, EuTiO3 using Quantum Espresso (DFT-U)

Follow up: Using a fixed occupation it was possible to get the dielectric constant since then QE won't treat the system as a metal anymore. Since STO is not stable at 0K, ph.x only showed imaginary ...
sAimen94's user avatar

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