ypp outputs for excitonic properties

[enorouzi]

Dear All

I have 2 problems. it's really kind of you to help me.

1: I use the below command to plot excitonic properties in Tio2 (rutile) unit cell:

ypp -e s
ypp -e a
ypp -e w

When I run ypp to make outputs I have the errors like this:

| | |/ | | | \ / \
| | | o | _ _ | o ) |
| ~ | | \_/ | | O |
|___, | _ | | | O | |
| | | | | | | |
|____/|__|__|___|___|_____|\___/

<---> [01] Y(ambo) P(ost)/(re) P(rocessor)
<---> [02] Core DB
<---> :: Electrons : 32.00000
<---> :: Temperature [ev]: 0.000000
<---> :: Lattice factors [a.u.]: 17.36318 17.36318 11.18302
<---> :: K points : 1
<---> :: Bands : 30
<---> :: Symmmetries : 2
<---> :: RL vectors : 7137
<---> [03] K-point grid
<---> :: Q-points (IBZ): 1
<---> :: X K-points (IBZ): 1
<---> [04] Input variables setup
<---> [04.01] Unit cells
<---> [04.02] Symmetries
<---> [04.03] RL shells
<---> [04.04] K-grid lattice
<---> [04.05] Energies [ev] & Occupations
<---> [05] Excitonic Properties

[ERROR] STOP signal received while in :[05] Excitonic Properties
[ERROR]Diago database does not contain excitonic wfs

How can I solve my problem?

2: How can I determine the hole positions in my system (Tio2 rutile unit cell)?

Best wishes

[Daniele Varsano]

Dear Ebrahim,

the problem is due to the fact that you have not saved the eigenvectors
of the excitonic matrix when solving the BS equation. In order to do that,
you have to use the solver "d" in yambo input
BSSmod= "d"
, and uncomment the flag
#WRbsWF # [BSS] Write to disk excitonic the FWs
in your input file. The flag appears when generating the yambo input
with verbosity, for instance:
yambo -o b -y d -V resp


In order to place the hole:
when you generate your input with ypp -e w
you place the hole in the unit cell:
% Hole
0.000 | 0.000 | 0.000 | # [cc] Hole position in unit cell
%

, then if you repeat your
unit cell in space along the directions you choose:
% Cells
1 | 1 | 1 | # Number of cell repetitions (even or 1)
%

the hole is then displaced accordingly. Then you can check the position of your hole
in the xsf file. I never tried with rutile cell, I hope it works.

Hope this helps,

Daniele