The effects of surface polarity and dangling bonds on the electronic properties of monolayer and bilayer MoS2 on α-quartz
We investigate the electronic properties of monolayer and bilayer MoS _2 on α -quartz substrate through first-principles density functional calculations. Due to the coupling of the MoS _2 with the substrate, the valence band edge state at the Brillouin zone center tends to shift upward, reducing the...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2014-01-01
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| Series: | New Journal of Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1367-2630/16/11/113055 |
| _version_ | 1797751517306945536 |
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| author | Ha-Jun Sung Duk-Hyun Choe K J Chang |
| author_facet | Ha-Jun Sung Duk-Hyun Choe K J Chang |
| author_sort | Ha-Jun Sung |
| collection | DOAJ |
| description | We investigate the electronic properties of monolayer and bilayer MoS _2 on α -quartz substrate through first-principles density functional calculations. Due to the coupling of the MoS _2 with the substrate, the valence band edge state at the Brillouin zone center tends to shift upward, reducing the indirect band gap of the MoS _2 , whereas the direct gap at the K valleys is less sensitive to substrate conditions. By taking into account the van der Waals interactions between the MoS _2 and the substrate, we find that monolayer MoS _2 exhibits a transition from direct-gap to indirect-gap semiconductor in the presence of surface O-dangling bonds. Moreover, a charge transfer occurs from MoS _2 to SiO _2 , inducing p -type doping and lifting the Kramers degeneracy by breaking the time reversal symmetry. In bilayer MoS _2 , O-dangling bonds break the inversion symmetry by inducing dipole fields across the interface and thereby lower the energy band associated with the one layer relative to the other. Although the time reversal symmetry is also broken, its effect on the spin splitting is extremely small in the K valleys so that a strong coupling between the spin and valley degrees of freedom takes place, similar to that found in free-standing monolayer MoS _2 . |
| first_indexed | 2024-03-12T16:50:38Z |
| format | Article |
| id | doaj.art-716eae9be24646c7aadd6187cdc3e605 |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:50:38Z |
| publishDate | 2014-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-716eae9be24646c7aadd6187cdc3e6052023-08-08T11:21:41ZengIOP PublishingNew Journal of Physics1367-26302014-01-01161111305510.1088/1367-2630/16/11/113055The effects of surface polarity and dangling bonds on the electronic properties of monolayer and bilayer MoS2 on α-quartzHa-Jun Sung0Duk-Hyun Choe1K J Chang2Department of Physics, Korea Advanced Institute of Science and Technology Daejeon 305-701, KoreaDepartment of Physics, Korea Advanced Institute of Science and Technology Daejeon 305-701, KoreaDepartment of Physics, Korea Advanced Institute of Science and Technology Daejeon 305-701, KoreaWe investigate the electronic properties of monolayer and bilayer MoS _2 on α -quartz substrate through first-principles density functional calculations. Due to the coupling of the MoS _2 with the substrate, the valence band edge state at the Brillouin zone center tends to shift upward, reducing the indirect band gap of the MoS _2 , whereas the direct gap at the K valleys is less sensitive to substrate conditions. By taking into account the van der Waals interactions between the MoS _2 and the substrate, we find that monolayer MoS _2 exhibits a transition from direct-gap to indirect-gap semiconductor in the presence of surface O-dangling bonds. Moreover, a charge transfer occurs from MoS _2 to SiO _2 , inducing p -type doping and lifting the Kramers degeneracy by breaking the time reversal symmetry. In bilayer MoS _2 , O-dangling bonds break the inversion symmetry by inducing dipole fields across the interface and thereby lower the energy band associated with the one layer relative to the other. Although the time reversal symmetry is also broken, its effect on the spin splitting is extremely small in the K valleys so that a strong coupling between the spin and valley degrees of freedom takes place, similar to that found in free-standing monolayer MoS _2 .https://doi.org/10.1088/1367-2630/16/11/113055electronic structuremolybdenum disulphidespin-orbit couplinglocal density functionalMoS271.15.Mb |
| spellingShingle | Ha-Jun Sung Duk-Hyun Choe K J Chang The effects of surface polarity and dangling bonds on the electronic properties of monolayer and bilayer MoS2 on α-quartz New Journal of Physics electronic structure molybdenum disulphide spin-orbit coupling local density functional MoS2 71.15.Mb |
| title | The effects of surface polarity and dangling bonds on the electronic properties of monolayer and bilayer MoS2 on α-quartz |
| title_full | The effects of surface polarity and dangling bonds on the electronic properties of monolayer and bilayer MoS2 on α-quartz |
| title_fullStr | The effects of surface polarity and dangling bonds on the electronic properties of monolayer and bilayer MoS2 on α-quartz |
| title_full_unstemmed | The effects of surface polarity and dangling bonds on the electronic properties of monolayer and bilayer MoS2 on α-quartz |
| title_short | The effects of surface polarity and dangling bonds on the electronic properties of monolayer and bilayer MoS2 on α-quartz |
| title_sort | effects of surface polarity and dangling bonds on the electronic properties of monolayer and bilayer mos2 on α quartz |
| topic | electronic structure molybdenum disulphide spin-orbit coupling local density functional MoS2 71.15.Mb |
| url | https://doi.org/10.1088/1367-2630/16/11/113055 |
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