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

[Zimmi Singh]

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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-- 
*Best Regards*
Zimmi Singh

*Research_Scholar *


*Department of Metallurgical and Materials Engineering Indian Institute of
Technology, Kharagpur Kharagpur, India*
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