How to obtain the correct 2D polarizability alpha_2D?
Posted: Wed Oct 19, 2022 9:13 am
Dear all,
I want to obtain the two-dimensional polarizability alpha_2D from RPA or BSE calculations. I noticed that there are two ways to do that: 1) calculate it directly from RPA, as in "PHYSICAL REVIEW B 84, 085406 (2011)"; 2) do BSE calculations and get the binding energy, then build a reliable low-energy model and adjust alpha_2D to match the model and first-principle binding energies, as in Nature Nanotechnology volume 15, 367–372 (2020).
I tried these two methods in 2D hBN systems. What confused me is that for a 18*18*1 calculation, the ALPHA-Re(\omega=0) (ALPHA0-Re also) in o-rpa.alpha_q1_inv_rpa_dyson file is different from the one in o-bse.alpha_q1_diago_bse file. Here are my questions:
1) I think the reason for this discrepancy is that I set BSE bands to 2-6, but set BndsRnXd in rpa to 1-60. Is that true?
2) If it's true, does it mean that the correct alpha_2D comes from the RPA output file?
The input and output files are attached.
Best wishes,
Huaiyuan
I want to obtain the two-dimensional polarizability alpha_2D from RPA or BSE calculations. I noticed that there are two ways to do that: 1) calculate it directly from RPA, as in "PHYSICAL REVIEW B 84, 085406 (2011)"; 2) do BSE calculations and get the binding energy, then build a reliable low-energy model and adjust alpha_2D to match the model and first-principle binding energies, as in Nature Nanotechnology volume 15, 367–372 (2020).
I tried these two methods in 2D hBN systems. What confused me is that for a 18*18*1 calculation, the ALPHA-Re(\omega=0) (ALPHA0-Re also) in o-rpa.alpha_q1_inv_rpa_dyson file is different from the one in o-bse.alpha_q1_diago_bse file. Here are my questions:
1) I think the reason for this discrepancy is that I set BSE bands to 2-6, but set BndsRnXd in rpa to 1-60. Is that true?
2) If it's true, does it mean that the correct alpha_2D comes from the RPA output file?
The input and output files are attached.
Best wishes,
Huaiyuan