Yambo Community Forum

Dear Prof. Daniele

A recent work (J. Mater. Chem. C, 2020, 8, 8856) pointed out that the effective dielectric tensor of 2D-materials can be defined as

How do I get the polarizability "\alpha_{2D}" by Yambo.

Best,
Pang

Dear Yuan,

you can either you system as 3D (i.e. without the inclusion of truncated Coulomb cutoff) and extract the alpha_2d performing calculation for different supercelll size as in Eq.16 of Cudazzo et al. PHYSICAL REVIEW B 84, 085406 (2011).

Otherwise, including the coulomb cutoff yambo print in output alpha defined as alpha=-X/q^2 where X is the response function.
Best,
Daniele

Dear Prof. Daniele

I have a new confusion. Does the "El. density" in the report file when solving the BSE, represents the density of electron-hole pairs (exciton)?

[07.01] QP corrections report
==============================

[X+QP] === General ===
[X+QP] Electronic Temperature : 0.000000 0.000000 [eV K]
[X+QP] Bosonic Temperature : 0.000000 0.000000 [eV K]
[X+QP] Finite Temperature mode : no
[X+QP] El. density : 0.13917E+24 [cm-3]
[X+QP] Fermi Level : -0.850359 [eV]

Best,
Pang

Dear Pang,
no, this is the electron density.

Best,
Daniele