Polarity‐Driven Atomic Displacements at the 2D Mg2TiO4‐MgO (001) Oxide Interface for Hosting Potential Interlayer Excitons
Abstract Interlayer excitons in solid‐state systems have emerged as candidates for realizing novel platforms ranging from excitonic transistors and optical qubits to exciton condensates. Interlayer excitons have been discovered in 2D transition metal dichalcogenides, with large exciton binding energ...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley-VCH
2023-04-01
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| Series: | Advanced Materials Interfaces |
| Subjects: | |
| Online Access: | https://doi.org/10.1002/admi.202202320 |
| _version_ | 1797772508117598208 |
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| author | Kidae Shin Stephen Eltinge Sangjae Lee Hyungki Shin Juan Jiang Hawoong Hong Bruce A. Davidson Ke Zou Sohrab Ismail‐Beigi Charles H. Ahn Frederick J. Walker |
| author_facet | Kidae Shin Stephen Eltinge Sangjae Lee Hyungki Shin Juan Jiang Hawoong Hong Bruce A. Davidson Ke Zou Sohrab Ismail‐Beigi Charles H. Ahn Frederick J. Walker |
| author_sort | Kidae Shin |
| collection | DOAJ |
| description | Abstract Interlayer excitons in solid‐state systems have emerged as candidates for realizing novel platforms ranging from excitonic transistors and optical qubits to exciton condensates. Interlayer excitons have been discovered in 2D transition metal dichalcogenides, with large exciton binding energies and the ability to form various van der Waals heterostructures. Here, an oxide system consisting of a single unit cell of Mg2TiO4 on MgO (001) is proposed as a platform for hosting interlayer excitons. Using a combination of density functional theory (DFT) calculations, molecular beam epitaxy growth, and in situ crystal truncation rod measurements, it is shown that the Mg2TiO4‐MgO interface can be precisely controlled to yield an internal electric field suitable for hosting interlayer excitons. The atoms in the polar Mg2TiO4 layers are observed to be displaced to reduce polarity at the interface with the non‐polar MgO (001) surface. Such polarity‐driven atomic displacements strongly affect electrostatics of the film and the interface, resulting in localization of filled and empty band‐edge states in different layers of the Mg2TiO4 film. The DFT calculations suggest that the electronic structure is favorable for localization of photoexcited electrons in the bottom layer and holes in the top layer, which may bind to form interlayer exciton states. |
| first_indexed | 2024-03-12T21:52:54Z |
| format | Article |
| id | doaj.art-2dfa60c9ff58499cafe1ad1df362fff2 |
| institution | Directory Open Access Journal |
| issn | 2196-7350 |
| language | English |
| last_indexed | 2024-03-12T21:52:54Z |
| publishDate | 2023-04-01 |
| publisher | Wiley-VCH |
| record_format | Article |
| series | Advanced Materials Interfaces |
| spelling | doaj.art-2dfa60c9ff58499cafe1ad1df362fff22023-07-26T01:35:19ZengWiley-VCHAdvanced Materials Interfaces2196-73502023-04-011010n/an/a10.1002/admi.202202320Polarity‐Driven Atomic Displacements at the 2D Mg2TiO4‐MgO (001) Oxide Interface for Hosting Potential Interlayer ExcitonsKidae Shin0Stephen Eltinge1Sangjae Lee2Hyungki Shin3Juan Jiang4Hawoong Hong5Bruce A. Davidson6Ke Zou7Sohrab Ismail‐Beigi8Charles H. Ahn9Frederick J. Walker10Department of Physics Yale University New Haven CT 06520 USADepartment of Physics Yale University New Haven CT 06520 USADepartment of Physics Yale University New Haven CT 06520 USADepartment of Physics & Astronomy University of British Columbia Vancouver British Columbia V6T 1Z1 CanadaDepartment of Applied Physics Yale University New Haven CT 06520 USAAdvanced Photon Source Argonne National Laboratory Argonne IL 60439 USADepartment of Physics & Astronomy University of British Columbia Vancouver British Columbia V6T 1Z1 CanadaDepartment of Physics & Astronomy University of British Columbia Vancouver British Columbia V6T 1Z1 CanadaDepartment of Physics Yale University New Haven CT 06520 USADepartment of Physics Yale University New Haven CT 06520 USADepartment of Applied Physics Yale University New Haven CT 06520 USAAbstract Interlayer excitons in solid‐state systems have emerged as candidates for realizing novel platforms ranging from excitonic transistors and optical qubits to exciton condensates. Interlayer excitons have been discovered in 2D transition metal dichalcogenides, with large exciton binding energies and the ability to form various van der Waals heterostructures. Here, an oxide system consisting of a single unit cell of Mg2TiO4 on MgO (001) is proposed as a platform for hosting interlayer excitons. Using a combination of density functional theory (DFT) calculations, molecular beam epitaxy growth, and in situ crystal truncation rod measurements, it is shown that the Mg2TiO4‐MgO interface can be precisely controlled to yield an internal electric field suitable for hosting interlayer excitons. The atoms in the polar Mg2TiO4 layers are observed to be displaced to reduce polarity at the interface with the non‐polar MgO (001) surface. Such polarity‐driven atomic displacements strongly affect electrostatics of the film and the interface, resulting in localization of filled and empty band‐edge states in different layers of the Mg2TiO4 film. The DFT calculations suggest that the electronic structure is favorable for localization of photoexcited electrons in the bottom layer and holes in the top layer, which may bind to form interlayer exciton states.https://doi.org/10.1002/admi.202202320density functional theoryinterlayer excitonsoxide thin filmsynchrotron X‐ray |
| spellingShingle | Kidae Shin Stephen Eltinge Sangjae Lee Hyungki Shin Juan Jiang Hawoong Hong Bruce A. Davidson Ke Zou Sohrab Ismail‐Beigi Charles H. Ahn Frederick J. Walker Polarity‐Driven Atomic Displacements at the 2D Mg2TiO4‐MgO (001) Oxide Interface for Hosting Potential Interlayer Excitons Advanced Materials Interfaces density functional theory interlayer excitons oxide thin film synchrotron X‐ray |
| title | Polarity‐Driven Atomic Displacements at the 2D Mg2TiO4‐MgO (001) Oxide Interface for Hosting Potential Interlayer Excitons |
| title_full | Polarity‐Driven Atomic Displacements at the 2D Mg2TiO4‐MgO (001) Oxide Interface for Hosting Potential Interlayer Excitons |
| title_fullStr | Polarity‐Driven Atomic Displacements at the 2D Mg2TiO4‐MgO (001) Oxide Interface for Hosting Potential Interlayer Excitons |
| title_full_unstemmed | Polarity‐Driven Atomic Displacements at the 2D Mg2TiO4‐MgO (001) Oxide Interface for Hosting Potential Interlayer Excitons |
| title_short | Polarity‐Driven Atomic Displacements at the 2D Mg2TiO4‐MgO (001) Oxide Interface for Hosting Potential Interlayer Excitons |
| title_sort | polarity driven atomic displacements at the 2d mg2tio4 mgo 001 oxide interface for hosting potential interlayer excitons |
| topic | density functional theory interlayer excitons oxide thin film synchrotron X‐ray |
| url | https://doi.org/10.1002/admi.202202320 |
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