yambo_surf cutoff behavior
Posted: Wed Feb 22, 2023 3:42 pm
Dear all,
I'm currently testing the Github branch "devel_surf" to compute reflection anisotropy spectra (RAS) for Si(001)-surfaces
and I encountered a weird behavior while using the cutoff feature.
I first calculated the dieletric function using the normal linear responds routine:
with
Then I did the same using the yambo_surf module:
leaving the cutoff variable commented (see test_without_cutoff.txt).
Afterwards I did and I uncommented the cutoff variable:
(see test_with_cutoff.txt)
In the end I plotted the resulting dieletric functions along the x-axis for all three calculation and compared them to
my previous VASP results (see eps_cmp.pdf). You can see that the VASP results match the ones from YAMBO very well
as long as the cutoff is disabled. With the cutoff varibles set to 0 and 1 I would assume that I would obtain the same result,
as we filter the whole unit cell but the resulting dielectric function does not match the previous calculation at all.
Did I use the cutoff in the wrong way or am I missing something else?
Thanks you for your help and support!
Best regards,
Max
I'm currently testing the Github branch "devel_surf" to compute reflection anisotropy spectra (RAS) for Si(001)-surfaces
and I encountered a weird behavior while using the cutoff feature.
I first calculated the dieletric function using the normal linear responds routine:
Code: Select all
yambo -o c -k h -F test_lr_optics.txt
Code: Select all
QpntsRXd 1 | 1 |
Code: Select all
yambo_surf -t r -F test_without_cutoff.txt
Afterwards I did
Code: Select all
yambo_surf -t r -F test_with_cutoff.txt
Code: Select all
Cutoff # [RAS] Cutoff mode (Uncomment to use)
CutZero= 0.000000 # [RAS] Zero position of cutoff fn (Frac)
CutStep= 1.000000 # [RAS] Width of cutoff function (Frac)
In the end I plotted the resulting dieletric functions along the x-axis for all three calculation and compared them to
my previous VASP results (see eps_cmp.pdf). You can see that the VASP results match the ones from YAMBO very well
as long as the cutoff is disabled. With the cutoff varibles set to 0 and 1 I would assume that I would obtain the same result,
as we filter the whole unit cell but the resulting dielectric function does not match the previous calculation at all.
Did I use the cutoff in the wrong way or am I missing something else?
Thanks you for your help and support!
Best regards,
Max