Questions tagged [dft-u]
Questions related to DFT+U, where U is an extra term involving the Hubbard potential.
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Bandgap calculations of a supercell using castep?
I am calculating the bandgap of the bismuth tungstate using castep in Materials Studio. The results are fairly accurate using the DFT+U approach.
However, there's no bandgap when I build a supercell ...
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0
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How to efficiently calculate Hubbard parameters using hp.x for isolated dopant?
Background
I know how to use hp.x in case of undoped periodic system. We take a small unit cell, apply some initial guess values to obtain the ground state (pw.x), and then run the hp.x on top of it ...
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How do we find the starting_ns_eigenvalue for QE calculations?
When performing DFT+U calculation, the ground state might get stuck in a local minimum. In such cases we need to provide starting_ns_eigenvalue to help the ...
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How to choose the best U value for studying the electronic properties?
I'm new to DFT+U and trying to understand how FeTiO3 works by looking at its electronic properties. But there's a big problem: when I use normal DFT, I can't get the w
right band-gap value.
How can I ...
- 4,761
2
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Temperature effect on electronic properties
I'm particularly interested in studying how temperature affects electronic properties. However, I've been working with Quantum Espresso and its DFT + U functionality, and I'm struggling to understand ...
- 101
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How to set the LMAXMIX tag in VASP for the material BaLaMn2O6?
I am trying to do DFT+U calculation for the material BaLaMn2O6 . As per the vaspwiki it is recommended to set LMAXMIX = 4 (d-elements) and ...
- 3,535
4
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DFT+U: localizing electrons on combination of atomic orbitals
TLDR: DFT+U is a cheap scheme to help localize electrons on atomic orbitals by penalizing fractional occupancies of such orbitals. However, when one tries to localize an electron/hole on an atomic ...
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Is DFT+U an ab initio based method? [duplicate]
As the title already states is DFT+U considered an ab initio method?
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How to calculate formation energy using DFT+U?
I noticed that a lot of articles use DFT+U methods to calculate different formation energies when using regular DFT and DFT+U methods. For example, in the attached paper[1] on $\ce{In2O3}$, the ...
9
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How To calculate formation energy of Ni doped ZnO system in Quantum ESPRESSO?
I have successfully completed the SCF of doped system Ni doped ZnO using GGA+U. I have checked the SCF.out file and found the energy value : E= -6112.0389 Ry.
Hwo to calculate the formation energy of ...
- 4,356
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d-d transitions in materials with transition metals in DFT
While reading the literature on the absorption spectra of materials from the MPX3 group (M= Mn,Ni,Co, Fe; layered antiferromagnets) I come across expressions such as d-d transitions, which are visible ...
- 15.7k
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Noncollinear band structure calculation with VASP
I am trying to do a band structure calculation of a noncollinear magnetic system. I am getting results that are nowhere close to what I'm expecting. I need help checking if I am following the right ...
- 8,257
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How to plot downfolded bands from DFT bands?
Once you mapped the high symmetry points from primitive cell to the super cell, you need to plot the downfolded bands.
As we know in DFT output of band structure calculation we get a set of E vs k ...
CommunityBot
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could meta-GGA-r2scan descript d electron localization and polaron the same as Hybrid functional?
I notice that r2scan could be more accurate than rscan, but I am unsure if r2scan could describe the d electron localization without Hubbard+U? Or do I still need Hubbard+U with r2scan?
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Hubbard U value on LaAlO3/SrTiO3 interface [closed]
I want to do a GGA+U calculation on the LaAlO3/SrTiO3 heterostructure to study the 2DEG formed at the interface. In all the references I came across they used U around 4eV-6eV on Ti 3d orbitals, I'm ...
4
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Query related to GGA+U calculation in SIESTA
I want to calculate the electronic band structure for CuWO4 using the GGA+U method. Is it necessary to optimize the structure using the same GGA+U method or only we can incorporate GGA+U parameter in ...
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Phonon Dispersion of SrTiO3, EuTiO3 using Quantum Espresso (DFT-U)
the last few days I've tried to calculate the phonon-dispersion of SrTiO3 (STO) and EuTiO3 (ETO) using the PHonon package of QE. SCF, DOS, PDOS and Bandsctructure calculation worked well on these ...
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DFT+U for RPA Ground State
For RPA calculations in VASP, a four step process can be utilized where the first step is to compute the occupied orbitals at either the GGA or hybrid GGA level.
I am curious with materials that are ...
- 11.4k
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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. ...
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Do the U values affect structure optimization with the DFT+U simulation to optimize crystal structure?
I am trying to do structure optimization of TiO2, since titanium is a transition metal, I need to use DFT+U to simulate the right band structure, but the electronic band structure would also affect ...
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How to create a CIF using VESTA? [closed]
I am looking into double perovskite materials. One of the possible materials is $\ce{Cs4CuSb2Cl12}$. Now, although there are a few papers which have done ab intio calculations but none of the common ...
- 15.7k
9
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In which conditions can the self-consistent Hubbard U value calculated using Quantum Espresso be used for other VASP calculations?
I have seen that some articles calculate Hubbard $U$ value self-consistently using Quantum Espresso code. Then, they use it in VASP calculations. My question is: In which conditions can this value be ...
- 11.4k
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How to perform linear response theory calculation of U Hubbard parameter in VASP?
Following to this post, I would like to know how to perform linear response theory for calculation of U Hubbard parameter in VASP?
- 11.4k
12
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Charge density convergence within VASP using spin polarized DFT+U
I am noticing a possible convergence problem in a magnetic $U$ system I am studying. In the OSZICAR file I often see the rms(c) value go to about ...
7
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Will there be a difference between GGA and GGA+$U$ for material with Sc element involved?
I have a material that contains the transition metal element Sc [3$d$1], and I want to know your opinions if there will be a difference between GGA and GGA+$U$ calculation. Knowing that the other ...
- 15.3k
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How to determine the value of the difference (U-J) in "Dudarev's approach" for GGA+U calculation using the VASP?
I want to conduct GGA+U calculations using Duradev's approach in VASP code on a ...
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How to use hp.x in Quantum ESPRESSO to calculate Hubbard parameter [closed]
I want to work with GGA +U on Quantum espresso to calculate the electronic properties of Ni Co co-doped ZnO system, but I can't figure out how to use the hp.x program for my system to calculate the ...
14
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Hubbard U correction for Copper
I am reviewing some information in the Materials Project and notice that they do not use DFT+U to model copper oxides. Since the methodology for fitting U is largely based on the 2006 Ceder paper, I ...
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Are there any good books to learn how to use DFT+U?
I am interested in learning how to do DFT+U calculations and was wondering if anyone has any good recommendations for books or articles.
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DFT+U Values from Reference Formation Energies
I would like to calculate some DFT+U values for a few elements (Fe, Co, Ni, Cu, Zn?) and am attempting to take the approach from the Ceder 2006 paper. Where does the Ceder paper take its experimental ...
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Determine DFT+U values by linear response
I am currently trying to determine how DFT+U values can be determined self consistently. I see that the bare and converged linear response matrix contain the difference in occupancies from the ground ...
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7
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2
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Apply DFT+U to Oxygen/Nitrogen p Orbitals
I often see DFT+U corrections for transition metals with delocalization problems, but a comment about applying a U correction to nitrogen or oxygen's p orbitals also shows up when digging around in ...
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Database or repository with values for the Hubbard potential U?
The Materials Project and other materials databases have a nice periodic table on their home page that allows you to search for compounds. For some materials, they give an empirical $U$ value used to ...
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