How to calculate the exciton effective mass if it is com

[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

[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

[plasmon]

Thank you!

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

[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

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

[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