[Pw_forum] Tuning Spin Orbit Coupling parameter

Niraj Aryal debonairniraj at gmail.com
Mon Jan 23 22:20:09 CET 2017


Dear Dr. Rui and QE experts,

Thank you for your response. I will try to look into Harrison's book and
come back later if I have more doubts.

I have a really ugly approach in mind, not sure if it is valid or not. Can
you (or someone) please comment on this?

Let's say I generate scalar and fully relativistic pseudopotential using
same parameters and find the difference between them at each grid point.
Can we call this difference the SOC term? If so, can I use a parameter
lambda (from 0 to 1) to scale the difference and then add back to the
scalar relativistic pseudopotential so that when lambda is 0, it is the
scalar relativistic PP and when lambda is 1, it is fully relativistic PP?

On Sat, Jan 21, 2017 at 5:24 PM, Rui Pang <taichizi at mail.ustc.edu.cn> wrote:

> Dear Niraj
> Usually it can be realized by fitting a tight binding model from a scarlar
> relativestic band structure and add the SOC in the TB model to recalculate
> the band structure. Detail of the later step can be found in the
> 'elementary electronic structure' by Harrison. But this method is without
> SCF.
> Someone told me that one can change the value of light`s speed to change
> the SOC. I am not sure if it works in QE.
> Best wishes.
> Pang Rui.
>
> -----原始邮件-----
> *发件人:*"Niraj Aryal" <debonairniraj at gmail.com>
> *发送时间:*2017-01-22 04:04:19 (星期日)
> *收件人:* pw_forum at pwscf.org
> *抄送:*
> *主题:* [Pw_forum] Tuning Spin Orbit Coupling parameter
>
>
> Dear QE experts,
>
> I am curious to study how the material properties vary as a function of
> spin orbit coupling  (SOC) strength.
>
> The motivation behind this is many e.g. I want to see numerically how the
> strength of SOC changes the band topology in topological insulators like
> Bi2Se3 or the possible metallic to insulating (or vice versa) phase change
> in materials with big SOC. Though this gives artificial material, this
> could possibly give more intuition in materials design.
>
> I know that it is possible and has been done for different purpose at
> least in this paper by Wang, Yates, Souzo and Vanderbilt:
> https://arxiv.org/pdf/cond-mat/0608257v1.pdf
>
> Can someone guide me on how to tune the SOC? I guess the tuning has to be
> done in the pseudopotential file itself, right? Is there some kind of
> flag/or parameter I can find in pseudopotential generation code like atomic
> to tune SOC?
>
> Are there any other ways?
>
> I would appreciate any response on this problem.
>
>
> With regards
>
> Niraj Aryal
> Graduate Student
> Florida State University
> Tallahassee, Florida-32304
>
>
> --
> Pang Rui, Lectureer
> School of physics and engneering
> Zhengzhou University
> China
>
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>



-- 
With regards

Niraj Aryal
Florida State University
Tallahassee, Florida-32304
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