Perhaps do a google search for correlated materials. For example, maybe
the following references are of interest:
https://en.wikipedia.org/wiki/Strongly_correlated_material#Electronic_structures
https://arxiv.org/abs/1309.3355v1 (Section 1. LDA+U vs Hartree-Fock and
Exact Exchange)
http://www.cond-mat.de/events/correl12/manuscripts/ (The LDA+U Approach:
A Simple Hubbard Correction for Correlated Ground States)
On 11/22/2016 3:28 AM, Luis Ogando wrote:
Thank you Pablo !
I am looking for something introductory like wikipedia. Do you have
some reference "in this direction" ?
All the best,
Luis
2016-11-21 15:25 GMT-02:00 delamora <delam...@unam.mx
<mailto:delam...@unam.mx>>:
Luis, look for Hubbard Model
NaCl U2
Pablo
------------------------------------------------------------------------
*De:* Wien <wien-boun...@zeus.theochem.tuwien.ac.at
<mailto:wien-boun...@zeus.theochem.tuwien.ac.at>> en nombre de
Luis Ogando <lcoda...@gmail.com <mailto:lcoda...@gmail.com>>
*Enviado:* lunes, 21 de noviembre de 2016 11:00:23 a. m.
*Para:* A Mailing list for WIEN2k users
*Asunto:* Re: [Wien] Hartree-Fock and the Hubbard Model
Dear Prof. Tran,
I would like to read more about this subject, but,
unfortunately, your link gave me a message like : " Wikipedia does
not have an article with this exact name. "
Please*,* could you suggest another non-specialist reference
like wikipedia ?
Thank you,
Luis
2016-11-20 13:28 GMT-02:00 <t...@theochem.tuwien.ac.at
<mailto:t...@theochem.tuwien.ac.at>>:
Hi,
DFT+U is a cheap but rather rough approximation of HF.
Beside this, there is also the difference that in DFT+U, the
Coulomb
operator is attenuated in order to account for the screening
due to
correlation. In HF, no correlation is included.
In hybrids, the screening is included by using only ~25% of HF
exchange
(and there is also correlation coming from a LDA/GGA
correlation term).
Hybrid, onsite-hybrid and DFT+U are more or less the same,
since all of them are one-electron methods and mix HF with
LDA/GGA.
As Karel said, they are better than LDA/GGA, but can not reproduce
the experimental observations that are beyond the one-electron
methods.
DMFT is better since it is a beyond one-electrons method.
Read that:
https://en.wikipedia.org/wiki/LDA+U
<https://en.wikipedia.org/wiki/LDA+U>
FT
On Wed, 16 Nov 2016, delamora wrote:
Dear Fabien Tran and Karel Vyborny,
Thanks for your comments.
What I want to know is if the Hartree Fock exchange is
what the Hubbard U is
trying to model
What I know is that for strong intraatomic repulsion, 3d
and 4f, the Hubbard
U gives good results, although the U is a parameter.
But for intermediate intraatomic repulsion, 4d, 5d, 5f
then more expensive
methods are needed, such as DMFT
So, if this is the case that the Hartree Fock exchange is
what the Hubbard U
is trying to model then the hybrid functionals would do a
better job.
So, my question is; What are the Hubbard U and DMFT trying
to model?
Cheers
Pablo de la Mora
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