Questions tagged [gw-bse]
Questions about the GW approximation or the Bethe-Salpeter Equation (BSE).
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Which strategy of improving the DFT band gap is the most effective?
DFT band gap problem is a well-known problem. LDA or GGA exchange-correlation functionals underestimate the band gap heavily. I saw some of the strategies to address this issue were:
using hybrid ...
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How is exciton binding energy calculated?
I am having some difficulties understanding values of exciton binding energies for $\ce{MoS2}$ monolayer. In various papers:
Interlayer and intralayer excitons in MoS2/WS2 and MoSe2/WSe2 ...
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Weighted average optical spectra in VASP
I am working on a 2D system where geometric and magnetic isomers are energetically very close to each other (orders of meV). I am interested in optical absorbance spectra using GW+BSE approach but I ...
- 31
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2
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Density Functional Perturbation Theory
What is the difference between density functional perturbation theory (DFPT) and many-body perturbation theory (MBPT)? Also, please help me understand why approximations like PBEsol are considered as ...
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Is the HOMO energy obtained from GW calculation always a value relative to the vacuum energy (-Ip)?
Aim:
I want to obtain a reasonably accurate ionization energy (or work function in other terms) for a 2-dimensional hBN monolayer. The exact material does not matter much respective to the question, ...
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Problem while performing the BSE GW calculations in VASP
I am trying to learn the BSE GW calculations in VASP. Using the procedure described on the VASP website.
I am stuck at the last step 5 (BSE calculation). I didn't get any error in the 5th step but ...
- 343
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1
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VASP GW PAW Pseudopotentials
What is the difference between the GW and non-GW potentials in VASP. While it is clear that the GW potentials should be used with GW calculations, the documentation also states that these potentials ...
- 10.8k
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VASP GW+SOC band structure calculations
How may I carry out GW+SOC a band structure calculation using VASP? Could anyone familiar describe it step-by-step? I could not find any info regarding this on the VASP wiki.
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KS-DFT versus G0W0
The central equation that KS-DFT will solve is:
$$\tag{1}\left[ -\dfrac{1}{2}\nabla^2+V_{ext}+V_{hartree}+V_{xc} \right]\psi_i(\vec{r})=E_i\psi_i(\vec{r})$$
Here $V_{xc}$ is approximated with LDA or ...
- 14.9k
8
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2
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How to plot exciton wave function with phase information?
In GW-BSE calculations, people could analyze the exciton wave function $|S\rangle$ by plotting the BSE eigenvector $A_{cv\mathbf{k}}$ that satisfies $|S\rangle = \sum_{cv\mathbf{k}}A_{cv\mathbf{k}}|cv\...
- 2,048
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How to evaluate the exciton velocity?
I have calculated the exciton wave functions using the GW-BSE method:
$$\tag{1}|S\rangle = \sum_{cv\mathbf{k}} A_{cv\mathbf{k}} |cv\mathbf{k}\rangle$$
where $c$ for conduction and $v$ for valence ...
- 2,048
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2
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Recommended code to do XAS/XES/RIXS calculations with?
I am a grad student looking to simulate several XAS/XES and potentially RIXS spectra for some strongly correlated metal-oxides. The materials in question will likely require solving the Bethe-Salpeter ...
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What are the recent developments of GW@BSE to simulate the excited properties of materials?
A twin question related to the TDDFT method is asked in another post. But any comparisons between both methods in recent developments are welcome.
The time-dependent density functional theory (TDDFT) ...
- 14.9k
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1
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What are the recent developments of TDDFT to simulate the excited properties of materials?
The time-dependent density functional theory (TDDFT) and the many-body perturbation method (GW@BSE) are considered as the two most popular and successful methods to describe the excited-stated ...
- 14.9k
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1
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BSE and IQP oscillator strength from VASP
Recently I am trying to calculate the BSE and IQP transition dipole based on VASP lecture on BSE and BSE fatband. However, I have a few questions regarding the BSE and IQP oscillator strength. From ...
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Is there a software that has implemented forces of BSE calculations for solids?
I'd like to investigate the structural relaxations of the excited state for periodic systems. It seems BSE is a practical method that has already been implemented in many codes for static calculations....
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What's the meaning of absorbance in the absorption spectrum calculated by the GW-BSE method?
Q1: As shown in the previous figure, what's the physical meaning of absorbance (y-axis) in the absorption spectrum calculated with the GW-BSE method?
Q2: Here the absorbance for the absorption onset $...
- 14.9k
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2
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What methods are available for excited state calculations in solids?
In the spirit of a succint answer (3 paragraphs maximum) to create a useful resource, what are the types of excited state calculation available for solids? Please add to the list:
Quasiparticle ...
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3
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Given that Kohn-Sham DFT is strictly a ground-state method (at 0 K), how is it sufficient to describe materials in real-life applications?
Kohn-Sham DFT appears to be so popular even though it is strictly a ground-state method - all calculations are done at 0 K. How then, is it so popular when describing materials that have real-life ...
- 2,426
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Can GW-BSE quasiparticle calculations only be run on norm-conserving pseudopotentials (NCPPs)? If so, why not?
I've read in some texts that GW-BSE quasiparticle calculations have only been implemented on Norm-conserving Pseudopotentials (and not Ultra-soft or PAW PPs). Is there a conceptual reason for this? I ...
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