About QP correction

[sdwang]

Dear Shudong,
it looks you have some band crossing. It can happens and it is possible that there is nothing wrong.
I suggest you to plot the band structures, and looks if, even the index of some bands are reversed,
the bands are continous.

Cheers,

Daniele

I plot the band structure, and as you said, some bands are crossing.But I note that in LDA energy, it does not occur.What is reason for the band crossing in GW band structure?
How can I solve this?
Thanks!
Merry Christmas！

[Daniele Varsano]

Dear Shudong,

I plot the band structure, and as you said, some bands are crossing.But I note that in LDA energy, it does not occur.What is reason for the band crossing in GW band structure?
How can I solve this?
Thanks!

Once you are sure that everything is at convergences and there are not artifact, try to understand on what's happening,
by looking at each part of the correction (exchange, correlation), plotting the wavefunctions in the along k-points and
crossing points, use more k-points to look what happen near the crossing (and look if they really cross!!) and whatever
you can have in mind to get some insight.


Best,

Daniele

[sdwang]

Dear developers:
I noticed in http://www.yambo-code.org/tutorials/Rea ... /index.php,
# K-point Band Eo Eqp E-Eo LDA HF Sc(Eo) Sc(Eqp) Sc`(Eo) Z
#
1.00000 3.00000 0.00000 -2.52528 -2.52528 -22.71821 -30.22404 4.46001 4.98054 -0.20612 0.82910
1.00000 4.00000 0.00000 -2.52208 -2.52208 -22.71822 -30.22392 4.46344 4.98361 -0.20624 0.82902
1.00000 5.00000 9.00799 10.95764 1.94965 -11.07205 -5.98616 -2.89262 -3.13624 -0.12495 0.88893
1.00000 6.00000 19.90535 22.23744 2.33210 -8.85649 -2.74308 -3.40730 -3.78131 -0.16034 0.86180
#
By plotting some of the o-PPA.qp columns it is possible to discuss some physical properties of the LiF QPs. Using columns 3 and 4 we can deduce the band gap renormalization and the stretching of the conduction/valence bands

In the plot, the band stretching is the slope of the fitting lines?