[QE-users] Difference in DOS intensity in QE and Yambo

[Giovanni Cantele]

Hi, while waiting for other answers, I would say that the differences
between the two are:
i) a small energy offset (as if one of the two Ef or both are not accurate
enough, I would check how zero energy is
fixed in the two cases);
ii) there is an overall factor of two that makes the two curves different.
While QE DOS takes into account the spin degree
of freedom, I'm not sure about that for Yambo.

Also check if the two DOS are calculated with the same smearing.
Giovanni
-- 

Giovanni Cantele, PhD
CNR-SPIN
c/o Dipartimento di Fisica
Universita' di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: giovanni.cantele at spin.cnr.it <giovanni.cantele at spin.cnr.it>
Phone: +39 081 676910
Skype contact: giocan74

ResearcherID: http://www.researcherid.com/rid/A-1951-2009
Web page: https://sites.google.com/view/giovanni-cantele/home


Il giorno dom 19 gen 2025 alle ore 15:10 Zimmi Singh <
singh.60 at kgpian.iitkgp.ac.in> ha scritto:

> Dear Prof. Paolo and Dr. Chang,
> Thank you, I appreciate your reply.
>
> We recently reached out to the YAMBO developers and learned that the
> density of states (DOS) is calculated in units of (states/Ha). Accordingly,
> we have replotted the DOS using Quantum ESPRESSO (QE) and YAMBO without
> applying any quasiparticle (QP) corrections, converting the units to states
> per electron volt (states/eV).
>
> The DOS plot generated without QP corrections is expected to be consistent
> with the results obtained from density functional theory (DFT) in QE.
> However, I have observed a notable discrepancy in the DOS intensity, as
> illustrated in the attached plot.
> I would appreciate your insights into the possible causes of this
> difference and any suggestions you might have to address or mitigate this
> issue.
>
> [image: Screenshot 2025-01-19 190142.jpg]
>
>
>
>
> On Wed, Jan 8, 2025 at 1:25 PM Chang, Xin <xin.chang at austin.utexas.edu>
> wrote:
>
>> Hello Zimmi,
>>
>>   Nice to meet you. The trend of your two calculations seems to be
>> reasonable. Because the G0W0 corrects the band gap with the quasi-particle
>> approach. If the parameters in your G0W0 calculation are reasonable (after
>> convergence test), the conduction band is elevated to a higher energy level
>> by quasi-particle correction. Please feel free to let me know if you still
>> have any questions. Best regards,
>> Xin
>>
>> ------------------------------
>> *发件人:* users <users-bounces at lists.quantum-espresso.org> 代表 Zimmi Singh <
>> singh.60 at kgpian.iitkgp.ac.in>
>> *发送时间:* 2025年1月7日 1:27
>> *收件人:* Quantum ESPRESSO users Forum <users at lists.quantum-espresso.org>
>> *主题:* [QE-users] Difference in DOS intensity in QE and Yambo
>>
>> Dear Developers and Community,
>>
>> I am plotting the density of states (DOS) using Density Functional Theory
>> (DFT) and the G0W0 method with the YAMBO code. However, I am observing
>> significant differences in the DOS intensity values. It appears to me that
>> both Quantum ESPRESSO (QE) and YAMBO do not normalize the DOS values over
>> the volume (unit: states/eV), so I would expect them to be similar, with
>> only minor shifts due to the increased band gap in the G0W0 results.
>> However, as shown in the attached picture, the DOS values differ
>> considerably by two orders of magnitude.
>>
>> I would greatly appreciate any suggestions or insights regarding other
>> factors that might cause this significant mismatch in DOS intensity.
>>
>> [image: dos.jpg]
>>
>> --
>> *Best Regards*
>> Zimmi Singh
>>
>> *Research_Scholar *
>>
>>
>> *Department of Metallurgical and Materials Engineering Indian Institute
>> of Technology, Kharagpur Kharagpur, India*
>>
>>
>> _______________________________________________________________________________
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>>
>> --------------------------------------------------------------------------------
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>> users mailing list users at lists.quantum-espresso.org
>> https://lists.quantum-espresso.org/mailman/listinfo/users
>>
>
>
> --
> *Best Regards*
> Zimmi Singh
>
> *Research_Scholar *
>
>
> *Department of Metallurgical and Materials Engineering Indian Institute of
> Technology, Kharagpur Kharagpur, India*
>
>
> _______________________________________________________________________________
> The Quantum ESPRESSO Foundation stands in solidarity with all civilians
> worldwide who are victims of terrorism, military aggression, and
> indiscriminate warfare.
>
> --------------------------------------------------------------------------------
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
> users mailing list users at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users
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