Re: [Phonopy-users] Whether the eigenvector in the band.yaml is equal to the eα?

[<ji...@ma...>]

Hi, Prof.Atsushi Togo,




I have another question about the eigenvector and Dynamical matrix. In your paper, entitled "First-principles Phonon Calculations with Phonopy and Phono3py", there are two type definitions of dynamical matrix, named C-TYPE and D-TYPE. I notice that the dynamical matrix in the Phonopy is C-TYPE. Am I right?




In the review, entitled "Electron-phonon interactions from first principles", the dynamical matrix is defined as D-type. If I want to use the formula in this review, I should transform the eigenvector via the equation (11) which is defined in your paper "First-principles Phonon Calculations with Phonopy and Phono3py". Am I right?




Thank you,




Professor.







-----原始邮件-----
发件人:"Atsushi Togo" <atz...@gm...>
发送时间:2024-09-05 19:58:54 (星期四)
收件人: pho...@li...
主题: Re: [Phonopy-users] Whether the eigenvector in the band.yaml is equal to the eα?


Hi,


Eigenvectors are computed using numpy eigh (https://numpy.org/doc/stable/reference/generated/numpy.linalg.eigh.html).
Dynamical matrix is defined by https://phonopy.github.io/phonopy/formulation.html#dynamical-matrix .
See also https://phonopy.github.io/phonopy/output-files.html#general


Togo


On Thu, Sep 5, 2024 at 6:07 PM jiangb--- via Phonopy-users <pho...@li...> wrote:


Dear Prof. Atsushi Togo,

 

I am writing this email to ask for your help. 

 

I use the phonopy to calculate the phonon and its eigenvector. However, I don't know whether the eigenvector in the band.yaml is equal to the eα (eβ) denoted in the Dynamical matrix part.  Some tutorials treat the eα as the product of the eigenvector in the band.yaml and the 1/M1/2.  Which one is right? 

 

And the axis of the eigenvector in the band.yaml confused me as well. The eigenvector in the band.yaml is along the xyz axis or along the a,b,c axis?




Jiang

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Atsushi Togo