Exciton wave function superposition

[lz dong]

Dear all,
I'm using "ypp -e w" to plot the exciton wavefunction for a given K point after a finished gw-BSE result. If K and -K are equivalent points, is the output exciton function the result of superposition of these equivalent K-points exciton functions? Or is it that only one K point is considered, and the phase superposition of these equivalent K points is not considered ?

Best Regards,

[Daniele Varsano]

Dear lz Dong,

I'm using "ypp -e w" to plot the exciton wavefunction for a given K point after a finished gw-BSE result.

what do you exactly means by "a given K point"?
The exciton wfs is build considering all the BZ with the relative weight given by the BSE eigenvectors.

Code: Select all

psi(re,rh)=\sum_vck |Acvk|^2 phi_v(rh) phi_c*(re)

All the BZ is considered and the phase are taken into account.

Best,
Daniele

[Davide Sangalli]

Dear Dong,
I guess you are thinking to the two degenerate excitons at K and K' in TMDC, which one can selectively pump with circularly polarized light..

For this specific case the answer is yes. Yambo will give two excitons which are two random (orthogonal) linear combinations of the two excitons at K and K'.

When plotting the wave-function at fixed hole position for example, it will sum over the two states to give you the electronic density in the two excitonic states.

Best,
D.