[QE-users] phonon dispersion relation from the full IFCs

[jqhuang16b at imr.ac.cn]

Thank you for reply, professor. I understand the regular routine implemented in QE where the long-range contribution is added in reciprocal space. My point is can I get the correct dynamical matrix just by making inverse Fourier transformation of the full(short+long) IFCs in a large real space?

-----原始邮件-----
发件人:"Stefano Baroni" <baroni at sissa.it>
发送时间:2020-01-08 21:55:26 (星期三)
收件人: "Quantum ESPRESSO users Forum" <users at lists.quantum-espresso.org>
抄送:
主题: Re: [QE-users] phonon dispersion relation from the full IFCs

The full dynamical matrix, including long-range forces, is computed by ph.x. The latter do not require any fine grid, but just the computation of Born effective charges, as explained in: P. Giannozzi et al, PRB 43, 7231 (1991), Eq. 18.  Regards — SB 



On 8 Jan 2020, at 13:49, jqhuang16b at imr.ac.cn wrote:


Dear all,


As we know, the short-ranged IFCs are available by QE. The dynamical matrices are obtained by making inverse Fourier transformation of the short-ranged IFCs, and then add back the long-ranged dipole-dipole contribution in the reciprocal space. This paper(X. Gonze et al, PRB 50. 13035 (1994)) provides the formula of long-ranged force constants. I wonder that is it feasible to obtain the correct phonon spectrum from the full IFCs(short+long)? Of course, the long-ranged IFCs should be gotten in a much longer range(maybe 100*100*100).


Any comments will be appreciated!


--


Jian-qi Huang

Magnetism and Magnetic Materials Division
Institute of Metal Research
Chinese Academy of Sciences
72 Wenhua Road, Shenyang 110016, China

email:jqhuang16b at imr.ac.cn





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