$piezcharge
piezcharge defines the polarization charge density difference between each layer. If there are 10 layers then we have 9 interfaces. So, we only need to set 9 regions.
Example
$piezcharge 0.00000e20 This means the polarization difference between layer 1 and 2 is 0.000. 1.00000e13 This means the polarization difference between layer 2 and 3 is 1.00000e13. It looks like positive interface charges. -1.00000e13 This means the polarization difference between layer 3 and 4 is -1.00000e13. It looks like negative interface charges. 1.00000e13 This means the polarization difference between layer 4 and 5 is 1.00000e13. It looks like positive interface charges. -1.00000e13 This means the polarization difference between layer 6 and 7 is 1.00000e13. It looks like positive interface charges. 1.00000e13 This means the polarization difference between layer 7 and 8 is -1.00000e13. It looks like negative interface charges. -1.00000e13 This means the polarization difference between layer 8 and 9 is 1.00000e13. it looks like positive interface charges. 1.00000e13 This means the polarization difference between layer 9 and 10 is -1.00000e13. it looks like negative interface charges . -1.00000e13
This means the polarization difference between layer 1 and 2 is 0.000. This means the polarization difference between layer 2 and 3 is 1.00000e13. It looks like positive interface charges. This means the polarization difference between layer 3 and 4 is -1.00000e13. It looks like negative interface charges. This means the polarization difference between layer 4 and 5 is 1.00000e13. It looks like positive interface charges. This means the polarization difference between layer 5 and 6 is -1.00000e13. It looks like negative interface charges. This means the polarization difference between layer 6 and 7 is 1.00000e13. It looks like positive interface charges. This means the polarization difference between layer 7 and 8 is -1.00000e13. It looks like negative interface charges. This means the polarization difference between layer 8 and 9 is 1.00000e13. it looks like positive interface charges. This means the polarization difference between layer 9 and 10 is -1.00000e13. it looks like negative interface charges .
