QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: baizq on July 20, 2021, 10:05

Title: ionic dielectric constant
Post by: baizq on July 20, 2021, 10:05

Dear All,

May I know how to calculate the ionic contribution to dielectric constant of materials? I have noticed that there is Optical spectrum functionality which returns dielectric tensor; but I guess this is just for the electronic contribution (correct me if I am wrong). Thanks !

Regards,
baizq

Title: Re: ionic dielectric constant
Post by: Anders Blom on July 21, 2021, 08:28

See https://docs.quantumatk.com/manual/Types/DielectricTensor/DielectricTensor.html and let us know if you have further questions :)

Title: Re: ionic dielectric constant
Post by: baizq on July 23, 2021, 11:16

Thank you Anders. I have a couple of quuestions regarding the SiO2 tutorial in the webpage you suggested.

1. In the optical spectrum session, huge number of bands are used (1000 bands above the fermi level and 1000 below). Why we need so many bands for such calculation?

2. In the DFT calculator setup, occupation_method is set as FermiDirac(100.0*Kelvin*boltzmann_constant). Why electron temperature is set to low value?