Dear L,
Thanks for your clear explanation, I understand it now.
Best Regards,
HY Lu
在 2023年11月15日 星期三 下午06:06:21 [GMT+8]， Lorenzo
Paulatto<[email protected]> 寫道：
Sorry but for 1 more naive question, if I use 2 unit cell instead of 1 in
DFPT, would it be expected to have difference between the two cases ( only at
Gamma point) ?
yes, it is different. Because you would get twice as many phonons, but half of
them would be periodic inside the supercell (and correspond to Gamma) the other
would not be (and correspond to a zone-border q-point).
hth
Best Regards,
HY Lu
在 2023年11月15日 星期三 下午03:56:04 [GMT+8]， Lorenzo
Paulatto<[email protected]> 寫道：
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On 15/11/2023 08:45, [email protected] wrote:
Hope this will give you an idea why such symmetry reduced supercell
calculation is being carried out.
The idea is "symmetry reduced".
I.e. DFPT allows you to simulate a monochromatic perturbation of any
periodicity with a unit cell, while frozen phonon can only simulate
perturbation which have the periodicity of the cell you are using. But to break
symmetry, you need a supercell.
kind regards
L
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--
Dr. Lorenzo Paulatto
IdR @ IMPMC - CNRS UMR 7590 & Sorbonne Université
phone: +33 (0)1 442 79822 / skype: paulatz
http://www.impmc.upmc.fr/~paulatto/ - https://anharmonic.github.io/
23-24/423 B115, 4 place Jussieu 75252 Paris CX 05
_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
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The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
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