[Pw_forum] Pressure-induced phase transition

[Hongsheng Zhao]

On 07/19/2011 08:15 AM, Hongsheng Zhao wrote:
>
> 1-  If you only use one type of initial phase to do this type of study.
>   Then you should use the vc-relax when changing the external pressure.
>   And then see what's the ultimate unit cell looks like for each
> pressure step.  For convenience, you can also plot the
> binding-energy/formation-energy vs external-pressure to see whether
> there are some abrupt change points - of course, there are many other
> physical properties you can consider to assist you judging the first
> order phase transition, I just give you a example here - on the plot.

Even in this case, you can also do the relax calculation for each 
external pressure step.  Then you plot the 
binding-energy/formation-energy vs external-pressure and find the abrupt 
change point on the plot.   Subsequently, you do the  vc-relax 
calculation for you system by imposing the pressure neighboring to 
abrupt change point and see what's you system should looks like.  By 
this method, you can save some computation times.

Best
-- 
Hongsheng Zhao <zhaohscas at yahoo.com.cn>
School of Physics and Electrical Information Science,
Ningxia University, Yinchuan 750021, China