Messages

1

General Questions and Answers / I have a question regarding the piezoelectric tensor manual.

« on: April 10, 2025, 11:37 »

Here are two ways to obtain the piezoelectric tensor using AlN as an example. The first method is to obtain e33 (piezoelectric tensor) by simply inserting the piezoelectric tensor block in the orthorhombic structure and running it. However, in the second method, the piezoelectric tensor block calculates the clamped-ion approximation. I wonder what criteria are used to obtain e33 (piezoelectric tensor) and e33(0) (the clamped ion approximation piezo tensor). I would appreciate it if you could clearly and specifically explain the difference between the two.
I would appreciate your reply.

2

General Questions and Answers / Why is the polarization value of AlN different from the experimental value?

« on: April 9, 2025, 08:58 »

I optimized AlN with a hybrid GGA using an LCAO calculator with a maximum force of 0.03 eV, and then obtained the polarization and piezo electric tensor, but they are very different from the experimental values. I would like to know the cause of this.

my AlN polarization data

my AlN piezoelectric tensor data


and reference data

3

General Questions and Answers / Re: Can QuantumATK calculates interface polarization?

« on: March 25, 2025, 06:03 »

I have an additional question. When materials A and B are combined in a hetero structure, the polarization of materials A and B are different. Then, the polarization should be different in two areas, but the result is only one polarization. Then, I wonder in which area this polarization was calculated (ex. A, B, A-B).

4

General Questions and Answers / Can QuantumATK calculates interface polarization?

« on: March 24, 2025, 12:36 »

I read the manual on polarization, but it only covers calculations for primitive cells, and I don't know if the polarization term can calculate polarization on the interface.
1st question : Is it possible to calculate polarization at the interface of a heterostructure in QuantumATK?
2nd question : How is the area for calculating polarization in QunatumATK polarization? ex) entire bulk configuration