[Pw_forum] About Electron-Phonon Coupling matrix element in QE4.2.1

[Eyvaz Isaev]

Hi, 

Just  a few words to be added concerning 

>In addition, I guess  " 0.318816E-08  0.318816E-08  0.318816E-08" 
>are the elctron-phonon coupling matrix elements. 

No, they are frequencies \omega^2 and  they are in Ry^2, consequently.

Bests,
Eyvaz
 -------------------------------------------------------------------
Prof. Eyvaz Isaev, 
Department of Physics, Chemistry, and Biology (IFM), Linkoping University, 
Sweden 

Theoretical Physics Department, Moscow State Institute of Steel & Alloys, 
Russia, 

isaev at ifm.liu.se, eyvaz_isaev at yahoo.com



----- Original Message ----
From: Eyvaz Isaev <eyvaz_isaev at yahoo.com>
To: PWSCF Forum <pw_forum at pwscf.org>
Sent: Wed, January 5, 2011 12:15:22 AM
Subject: Re: [Pw_forum] About Electron-Phonon Coupling matrix element in QE4.2.1

Dear  Cheng,

>The "0.000000      0.000000      0.000000    " in the top line is the
>q vector. What do the "10" and "3" mean?

10 is  the number of broadening parameters (\sigma) to calculate  the phonon 
linewidth due to electron-phonon interaction which contains  production of 
double delta functions  (so called gamma-function, for definitions please have a 

look at recently cited reference: http://arxiv.org/pdf/cond-mat/0504077
Starting value for \sigma is 0.005, final value is 0.05, this done to see how 
\lambda  is converged with respect to \sigma.

3 means modes number, in Al, sure, there are 3 modes.

>In addition, I guess  " 0.318816E-08  0.318816E-08  0.318816E-08" 

>are the elctron-phonon coupling matrix elements. 

No, they are frequencies in Ry.

>What is unit of elctron-phonon coupling matrix element?

Ry.

Bests,
Eyvaz.
-------------------------------------------------------------------
Prof. Eyvaz Isaev, 
Department of Physics, Chemistry, and Biology (IFM), Linkoping University, 
Sweden 

Theoretical Physics Department, Moscow State Institute of Steel & Alloys, 
Russia, 

isaev at ifm.liu.se, eyvaz_isaev at yahoo.com



----- Original Message ----
From: 程迎春 <yccheng.nju at gmail.com>
To: pw_forum at pwscf.org
Sent: Tue, January 4, 2011 10:24:49 PM
Subject: [Pw_forum] About Electron-Phonon Coupling matrix element in QE4.2.1

Dear PWscf users,

In example07 in QE4.2.1, one can calculate electron phonon coupling in
Al. I have a question about the elctron-phonon coupling matrix element
unit in the ph.x output file. For example, there are some lines in the
file "elph. 0.000000. 0.000000. 0.000000" as following:
==============================================
           0.000000      0.000000      0.000000    10     3
  0.318816E-08  0.318816E-08  0.318816E-08
     Gaussian Broadening:   0.005 Ry, ngauss=   0
     DOS =  1.338727 states/spin/Ry/Unit Cell at Ef=  8.321708 eV
     lambda( 1)=  0.0000   gamma=    0.00 GHz
     lambda( 2)=  0.0000   gamma=    0.00 GHz
     lambda( 3)=  0.0000   gamma=    0.00 GHz
     Gaussian Broadening:   0.010 Ry, ngauss=   0
......
==============================================
The "0.000000      0.000000      0.000000    " in the top line is the
q vector. What do the "10" and "3" mean?
In addition, I guess  " 0.318816E-08  0.318816E-08  0.318816E-08" in
the second line are the elctron-phonon coupling matrix elements. What
is unit of elctron-phonon coupling matrix element?

Thank you in advance.

Bests,
-- 
Y. C. Cheng
Department of Physics
Nanjing University
Nanjing 210093
P. R. China
Tel: 86-25-83592907
Email: yccheng.nju at gmail.com
_______________________________________________
Pw_forum mailing list
Pw_forum at pwscf.org
http://www.democritos.it/mailman/listinfo/pw_forum



      
_______________________________________________
Pw_forum mailing list
Pw_forum at pwscf.org
http://www.democritos.it/mailman/listinfo/pw_forum