10 votes

Difficulty in interpreting electronic band structures in solid state physics

One important step is to know how the Fermi energy ($E_F$) was treated. Some authors like to shift the band diagram after making $E_F=0$ (as looks like it was the case in the reference you cited) but ...
Camps's user avatar
  • 22.3k
9 votes

What makes the inhomogeneous electron gas more interesting than its homogeneous counterpart?

The homogeneous electron gas is a fiction: it represents a system that is completely uniform and that has a constant, smooth positive background charge to make the system charge neutral. However, the ...
Susi Lehtola's user avatar
8 votes

Simulated STM Image with Quantum-ESPRESSO's pp.x

A minimal input file For simulated STM, you can use pp.x. A minimal input file might look like this: ...
Abdul Muhaymin's user avatar
8 votes

What makes the inhomogeneous electron gas more interesting than its homogeneous counterpart?

In contemporary Kohn-Sham DFT, the exchange and correlation energies are local quantities. If the electron density is slowly varying, the LDA form derived from a uniform electron gas is a zero'th ...
Frank Jensen's user avatar
  • 1,311
7 votes

I'm considering to take an introduction course with textbook "Materials Science and Engineering: An Introduction", as a beginner QE user. Is it okay?

I am no expert or experienced in this field. All my suggestions are based on my own experience as a beginner in matter modeling. About the textbook This textbook you mentioned is sufficient for a ...
Abdul Muhaymin's user avatar
7 votes

Why do we not get DOS by summing over all the PDOS?

The fundamental problem is that the basis set used for the partial density-of-states (PDOS) does not span the plane-wave basis set space, so it is not usually possible to represent the Kohn-Sham ...
Phil Hasnip's user avatar
  • 6,582
5 votes

Optimzation for Large supercell

It should be possible to use Quantum Espresso to handle more than 200 atoms. I guess you are studying a surface, in that case, please note that in PW-based codes the vacuum makes your calculation more ...
Laura's user avatar
  • 967
5 votes

In solids physics, how are Van Der Waals forces modelled?

The documentation for pw.x, version 7.2, lists several different ways to compute van der Waals corrections: Grimme's semiempirical DFT-D2 and DFT-D3; Tkatchenko–...
elutionary's user avatar
4 votes

Negative band gap in DFT calculations

Some materials erroneously give a metallic state even if it isn’t. Depending on what type of material and exchange-correlation functional you use, this can be more or less likely to happen. With ...
AGS's user avatar
  • 1,050
3 votes

Can specifications of a second-order phase transition of a solid be obtained with the Hartree-Fock (or DFT) calculation?

In classic DFT approach you run geometry optimization for both phases which gives you electronic energies, then compute frequencies which gives you thermodynamic parameters, including tempurature-...
Ivan Chernyshov's user avatar
2 votes

How is magnetization of a solid obtained from electron density in a DFT framework?

The main keyword you are looking for is the spin-polarized DFT. Other keywords that might help you are the spin-density matrix, the Hubbard model (DFT+U), the Stoner Model, von Barth-Hedin spin-...
Abdul Muhaymin's user avatar
1 vote

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
  • 401

Only top scored, non community-wiki answers of a minimum length are eligible