Excitons in nonlinear optical responses: shift current in MoS2 and GeS monolayers
Abstract It is well-known that exciton effects are determinant to understanding the optical absorption spectrum of low-dimensional materials. However, the role of excitons in nonlinear optical responses has been much less investigated at the experimental level. Additionally, computational methods to...
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2025-01-01
|
| Series: | npj Computational Materials |
| Online Access: | https://doi.org/10.1038/s41524-024-01504-2 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1832594584973082624 |
|---|---|
| author | J. J. Esteve-Paredes M. A. García-Blázquez A. J. Uría-Álvarez M. Camarasa-Gómez J. J. Palacios |
| author_facet | J. J. Esteve-Paredes M. A. García-Blázquez A. J. Uría-Álvarez M. Camarasa-Gómez J. J. Palacios |
| author_sort | J. J. Esteve-Paredes |
| collection | DOAJ |
| description | Abstract It is well-known that exciton effects are determinant to understanding the optical absorption spectrum of low-dimensional materials. However, the role of excitons in nonlinear optical responses has been much less investigated at the experimental level. Additionally, computational methods to calculate nonlinear conductivities in real materials are still not widespread, particularly taking into account excitonic interactions. We present a methodology to calculate the excitonic second-order optical responses in 2D materials relying on: (i) ab initio tight-binding Hamiltonians obtained by Wannier interpolation and (ii) solving the Bethe-Salpeter equation with effective electron-hole interactions. Here, in particular, we explore the role of excitons in the shift current of monolayer materials. Focusing on MoS2 and GeS monolayer systems, our results show that 2p-like excitons, which are dark in the linear response regime, yield a contribution to the photocurrent comparable to that of 1s-like excitons. Under radiation with intensity ~104W/cm2, the excitonic theory predicts in-gap photogalvanic currents of almost ~10 nA in sufficiently clean samples, which is typically one order of magnitude higher than the value predicted by independent-particle theory near the band edge. |
| format | Article |
| id | doaj-art-e28d1a33eb63491c9afbca649d56498b |
| institution | Kabale University |
| issn | 2057-3960 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | npj Computational Materials |
| spelling | doaj-art-e28d1a33eb63491c9afbca649d56498b2025-01-19T12:32:28ZengNature Portfolionpj Computational Materials2057-39602025-01-0111111010.1038/s41524-024-01504-2Excitons in nonlinear optical responses: shift current in MoS2 and GeS monolayersJ. J. Esteve-Paredes0M. A. García-Blázquez1A. J. Uría-Álvarez2M. Camarasa-Gómez3J. J. Palacios4Departamento de Física de la Materia Condensada, Universidad Autónoma de MadridDepartamento de Física de la Materia Condensada, Universidad Autónoma de MadridDepartamento de Física de la Materia Condensada, Universidad Autónoma de MadridDepartment of Molecular Chemistry and Materials Science, Weizmann Institute of ScienceDepartamento de Física de la Materia Condensada, Universidad Autónoma de MadridAbstract It is well-known that exciton effects are determinant to understanding the optical absorption spectrum of low-dimensional materials. However, the role of excitons in nonlinear optical responses has been much less investigated at the experimental level. Additionally, computational methods to calculate nonlinear conductivities in real materials are still not widespread, particularly taking into account excitonic interactions. We present a methodology to calculate the excitonic second-order optical responses in 2D materials relying on: (i) ab initio tight-binding Hamiltonians obtained by Wannier interpolation and (ii) solving the Bethe-Salpeter equation with effective electron-hole interactions. Here, in particular, we explore the role of excitons in the shift current of monolayer materials. Focusing on MoS2 and GeS monolayer systems, our results show that 2p-like excitons, which are dark in the linear response regime, yield a contribution to the photocurrent comparable to that of 1s-like excitons. Under radiation with intensity ~104W/cm2, the excitonic theory predicts in-gap photogalvanic currents of almost ~10 nA in sufficiently clean samples, which is typically one order of magnitude higher than the value predicted by independent-particle theory near the band edge.https://doi.org/10.1038/s41524-024-01504-2 |
| spellingShingle | J. J. Esteve-Paredes M. A. García-Blázquez A. J. Uría-Álvarez M. Camarasa-Gómez J. J. Palacios Excitons in nonlinear optical responses: shift current in MoS2 and GeS monolayers npj Computational Materials |
| title | Excitons in nonlinear optical responses: shift current in MoS2 and GeS monolayers |
| title_full | Excitons in nonlinear optical responses: shift current in MoS2 and GeS monolayers |
| title_fullStr | Excitons in nonlinear optical responses: shift current in MoS2 and GeS monolayers |
| title_full_unstemmed | Excitons in nonlinear optical responses: shift current in MoS2 and GeS monolayers |
| title_short | Excitons in nonlinear optical responses: shift current in MoS2 and GeS monolayers |
| title_sort | excitons in nonlinear optical responses shift current in mos2 and ges monolayers |
| url | https://doi.org/10.1038/s41524-024-01504-2 |
| work_keys_str_mv | AT jjesteveparedes excitonsinnonlinearopticalresponsesshiftcurrentinmos2andgesmonolayers AT magarciablazquez excitonsinnonlinearopticalresponsesshiftcurrentinmos2andgesmonolayers AT ajuriaalvarez excitonsinnonlinearopticalresponsesshiftcurrentinmos2andgesmonolayers AT mcamarasagomez excitonsinnonlinearopticalresponsesshiftcurrentinmos2andgesmonolayers AT jjpalacios excitonsinnonlinearopticalresponsesshiftcurrentinmos2andgesmonolayers |