Accelerating GW in 2D systems
Since Yambo v5.1 it is possible to use an algorithm able to accelerate convergences of GW calculations in two-dimensional systems with respect to the k point sampling.
The method is explained in the paper:
Efficient GW calculations in two-dimensional materials through a stochastic integration of the screened potential
A. Guandalini, P. D'Amico, A. Ferretti and D. Varsano
available at the link: https://arxiv.org/abs/2205.11946
The method makes use of a truncated Coulomb potential in a slab geometry that in Fourier space reads:
[math]\displaystyle{ V_G(q)=\frac{4\pi}{\vert q+G \vert^2}[1-e^{-\vert q_\parallel+G_\parallel\vert L/2}cos[(q_z+G_z)L/2)] }[/math]
where L is the length of the cell in the non-periodic z direction. As the q-grid is 2D, we have [math]\displaystyle{ q_z = 0. }[/math]