[QE-users] 回复: Effective mass and the unit of k

[jiale shen]

Thanks for your reply! But I’m still confused about the unit of k, and I compared two systems, one Si and the other my structure. The band calculations were performed with VASP and QE respectively, and the exported data classified and sorted out. For the convenience of presentation, I only copied the first 15 data points here. The first column below is the k value in BAND.dat that I output through vaspkit program, the second column is the k value in the exported data through the analysis of vasprun.xml by p4vasp, and the third column is the k value of the exported data through the bands. x module of qe6.6. The unit of vaspkit output k is known to be 1/A, and the unit of vasprun.xml is 2pi/A. The two units of qe output confuse me, for the Si system, I think the unit is 1/Bohr, whereas in the other system it is obviously not 1/Bohr. Why are the data output by QE's bands.x so different in unit?

Si system
k-vaspkit          k-vasprun.xml        k-QE
1/A                   2pi/A                  ?
0                       0                        0
0.06121            0.00974              0.0354
0.12241            0.01948              0.0707
0.18362             0.02922             0.1061
0.24482            0.03896              0.1414
0.30603             0.04871             0.1768
0.36723             0.05845             0.2121
0.42844             0.06819             0.2475
0.48964             0.07793             0.2828
0.55085             0.08767             0.3182
0.61206             0.09741             0.3536
0.67326             0.10715             0.3889
0.73447             0.11689             0.4243
0.79567             0.12664             0.4596
0.85688             0.13638             0.495

My system
k-vaspkit          k-vasprun.xml        k-QE
1/A                   2pi/A                 ?
0                       0                        0
0.019                0.00302              0.0174
0.038                0.00605              0.0347
0.05699            0.00907              0.0521
0.07599            0.01209              0.0694
0.09499            0.01512              0.0868
0.11399            0.01814              0.1042
0.13299            0.02117              0.1215
0.15198            0.02419              0.1389
0.17098            0.02721              0.1562
0.18998            0.03024              0.1736
0.20898            0.03326              0.191
0.22798            0.03628              0.2083
0.24697            0.03931              0.2257
0.26597            0.04233              0.243

--
Best Regards
Jiale Shen
Ph.D. Student
Beijing Institute of Technology

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发件人: Paolo Giannozzi<mailto:paolo.giannozzi at uniud.it>
发送时间: 2023年3月24日 15:32
收件人: Quantum ESPRESSO users Forum<mailto:users at lists.quantum-espresso.org>
抄送: jiale shen<mailto:shenjiale618 at outlook.com>
主题: Re: [QE-users] Effective mass and the unit of k

Usually k-points in band plots are in 2\pi/a units

On 23/03/2023 18:54, jiale shen wrote:
>
> You don't often get email from shenjiale618 at outlook.com. Learn why this
> is important <https://aka.ms/LearnAboutSenderIdentification>
>
>
> Dear QE users:
>
> I want to fit the bandstructure data calculated by qe6.6 to obtain the
> effective mass. We used the bands. x module to obtain the band.dat.gnu.
> What is the unit of the first column k? For example, the first column
> unit given by vaspkit is 1/A. Does anyone know the exact unit of the
> first column obtained by bands. x? "CELL_PARAMETERS (angstrom)" set in
> my input file.Any procedure on QE calculate the effective mass of 3D
> system?**
>
> --
>
>
> Best Regards
> Jiale Shen
> Ph.D. Student**
>
> Beijing Institute of Technology
>
> 从Windows 版邮件
> <https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F
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--
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 206, 33100 Udine Italy, +39-0432-558216

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