[Pw_forum] piezoelectricity

[hamid hasanzadeh]

hello dear all
I am working on piezoelectricity properties of materials
I runed example 10 in quantum espresso but i am not Purpose of  some
parameters in input and output files.
I get the value of born effective charge (for the all atoms PbTio3).
1-what is the meaning of the berry phase in output of PbTio3?
2-Can i get components of berry phase related to piezoelectric
constant? what i put in input of PbTiO3?

HAMID HASSANZADEH
M.Sc STUDENT OF Iran