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How to calculate the exciton effective mass if it is com
Posted: Fri Sep 24, 2021 2:06 pm
by plasmon
Dear Developers,
When I used YAMBO to calculate the exciton properties of two-dimensional materials, I found that, some exciton is composed of several bound electron-hole pairs with respective non-trivial oscillator strengths. Could you please tell me how to calculate the reduced effective mass for this kind of exciton? Thank you!
With best regards,
Hao
Re: How to calculate the exciton effective mass if it is com
Posted: Fri Sep 24, 2021 2:38 pm
by Daniele Varsano
Dear Hao,
If the effective mass approximation holds the effective mass is Meff=Me+Mh, see for instance:
G. Dresselhaus: J. Phys. Chem. Solids. vol. 1 pp 14 (1956)
Otherwise you can compute the exciton band structure, i.e. solving the BSE at finite momentum which has been recently released in Yambo ( version 5.x). Next you can extract the effective mass from the exciton band structure.
Best,
Daniele
Re: How to calculate the exciton effective mass if it is com
Posted: Sat Sep 25, 2021 1:15 pm
by plasmon
Thank you!
Daniele Varsano wrote: ↑Fri Sep 24, 2021 2:38 pm
Dear Hao,
If the effective mass approximation holds the effective mass is Meff=Me+Mh, see for instance:
G. Dresselhaus: J. Phys. Chem. Solids. vol. 1 pp 14 (1956)
Otherwise you can compute the exciton band structure, i.e. solving the BSE at finite momentum which has been recently released in Yambo ( version 5.x). Next you can extract the effective mass from the exciton band structure.
Best,
Daniele
Re: How to calculate the exciton effective mass if it is com
Posted: Wed Sep 29, 2021 8:54 am
by plasmon
Dear Prof. Varsano,
The Q-mesh in the exciton bandstructures calculated by YAMBO is not dense enough around the VBM and CBM for a precise calculation of exciton effective masses. Could you please tell me how to set some special Q-mesh points when calculating exciton bandstructures? Thank you very much!
With best regards,
Hao
Daniele Varsano wrote: ↑Fri Sep 24, 2021 2:38 pm
Dear Hao,
If the effective mass approximation holds the effective mass is Meff=Me+Mh, see for instance:
G. Dresselhaus: J. Phys. Chem. Solids. vol. 1 pp 14 (1956)
Otherwise you can compute the exciton band structure, i.e. solving the BSE at finite momentum which has been recently released in Yambo ( version 5.x). Next you can extract the effective mass from the exciton band structure.
Best,
Daniele
Re: How to calculate the exciton effective mass if it is com
Posted: Wed Sep 29, 2021 9:06 am
by Daniele Varsano
Dear Hao,
the exciton band structure can be interpolated using ypp (from yambo 5.x).
You can find here and example on how to generate the input file and use it:
http://www.yambo-code.org/wiki/index.ph ... mbo_5.x.29
Best,
Daniele