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Catanzaro A, Genco A, Louca C, Ruiz-Tijerina DA, Gillard DJ, Sortino L, Kozikov A, Alexeev EM, Pisoni R, Hague L, Watanabe K, Taniguchi T, Ensslin K, Novoselov KS, Fal'ko V, Tartakovskii AI. Resonant Band Hybridization in Alloyed Transition Metal Dichalcogenide Heterobilayers. Adv Mater 2024; 36:e2309644. [PMID: 38279553 DOI: 10.1002/adma.202309644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/20/2023] [Indexed: 01/28/2024]
Abstract
Bandstructure engineering using alloying is widely utilized for achieving optimized performance in modern semiconductor devices. While alloying has been studied in monolayer transition metal dichalcogenides, its application in van der Waals heterostructures built from atomically thin layers is largely unexplored. Here, heterobilayers made from monolayers of WSe2 (or MoSe2) and MoxW1 - xSe2 alloy are fabricated and nontrivial tuning of the resultant bandstructure is observed as a function of concentration x. This evolution is monitored by measuring the energy of photoluminescence (PL) of the interlayer exciton (IX) composed of an electron and hole residing in different monolayers. In MoxW1 - xSe2/WSe2, a strong IX energy shift of ≈100 meV is observed for x varied from 1 to 0.6. However, for x < 0.6 this shift saturates and the IX PL energy asymptotically approaches that of the indirect bandgap in bilayer WSe2. This observation is theoretically interpreted as the strong variation of the conduction band K valley for x > 0.6, with IX PL arising from the K - K transition, while for x < 0.6, the bandstructure hybridization becomes prevalent leading to the dominating momentum-indirect K - Q transition. This bandstructure hybridization is accompanied with strong modification of IX PL dynamics and nonlinear exciton properties. This work provides foundation for bandstructure engineering in van der Waals heterostructures highlighting the importance of hybridization effects and opening a way to devices with accurately tailored electronic properties.
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Affiliation(s)
- Alessandro Catanzaro
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
| | - Armando Genco
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy
| | - Charalambos Louca
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy
| | - David A Ruiz-Tijerina
- Departamento de Física Química, Instituto de Física, Universidad Nacional Autónoma de México, Ciudad de México, C.P., 04510, Mexico, México
| | - Daniel J Gillard
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
| | - Luca Sortino
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
- Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, 80539, Munich, Germany
| | - Aleksey Kozikov
- Department of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK
- School of Mathematics, Statistics and Physics, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Evgeny M Alexeev
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
- Cambridge Graphene Centre, University of Cambridge, 9 J. J. Thomson Avenue, Cambridge, CB3 0FA, UK
| | - Riccardo Pisoni
- Solid State Physics Laboratory, ETH Zurich, Zurich, CH-8093, Switzerland
| | - Lee Hague
- National Graphene Institute, University of Manchester, Manchester, M13 9PL, UK
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Klaus Ensslin
- Solid State Physics Laboratory, ETH Zurich, Zurich, CH-8093, Switzerland
| | - Kostya S Novoselov
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, 117546, Singapore
| | - Vladimir Fal'ko
- Department of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK
- Henry Royce Institute for Advanced Materials, University of Manchester, Manchester, M13 9PL, United Kingdom
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Barrier J, Kim M, Kumar RK, Xin N, Kumaravadivel P, Hague L, Nguyen E, Berdyugin AI, Moulsdale C, Enaldiev VV, Prance JR, Koppens FHL, Gorbachev RV, Watanabe K, Taniguchi T, Glazman LI, Grigorieva IV, Fal'ko VI, Geim AK. One-dimensional proximity superconductivity in the quantum Hall regime. Nature 2024; 628:741-745. [PMID: 38658686 DOI: 10.1038/s41586-024-07271-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 03/05/2024] [Indexed: 04/26/2024]
Abstract
Extensive efforts have been undertaken to combine superconductivity and the quantum Hall effect so that Cooper-pair transport between superconducting electrodes in Josephson junctions is mediated by one-dimensional edge states1-6. This interest has been motivated by prospects of finding new physics, including topologically protected quasiparticles7-9, but also extends into metrology and device applications10-13. So far it has proven challenging to achieve detectable supercurrents through quantum Hall conductors2,3,6. Here we show that domain walls in minimally twisted bilayer graphene14-18 support exceptionally robust proximity superconductivity in the quantum Hall regime, allowing Josephson junctions to operate in fields close to the upper critical field of superconducting electrodes. The critical current is found to be non-oscillatory and practically unchanging over the entire range of quantizing fields, with its value being limited by the quantum conductance of ballistic, strictly one-dimensional, electronic channels residing within the domain walls. The system described is unique in its ability to support Andreev bound states at quantizing fields and offers many interesting directions for further exploration.
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Affiliation(s)
- Julien Barrier
- Department of Physics and Astronomy, University of Manchester, Manchester, UK.
- National Graphene Institute, University of Manchester, Manchester, UK.
| | - Minsoo Kim
- Department of Physics and Astronomy, University of Manchester, Manchester, UK
- Department of Applied Physics, Kyung Hee University, Yong-in, South Korea
| | - Roshan Krishna Kumar
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, Spain
| | - Na Xin
- Department of Physics and Astronomy, University of Manchester, Manchester, UK.
- Department of Chemistry, Zhejiang University, Hangzhou, China.
| | - P Kumaravadivel
- Department of Physics and Astronomy, University of Manchester, Manchester, UK
- National Graphene Institute, University of Manchester, Manchester, UK
| | - Lee Hague
- National Graphene Institute, University of Manchester, Manchester, UK
| | - E Nguyen
- Department of Physics and Astronomy, University of Manchester, Manchester, UK
- National Graphene Institute, University of Manchester, Manchester, UK
| | - A I Berdyugin
- Department of Physics and Astronomy, University of Manchester, Manchester, UK
- National Graphene Institute, University of Manchester, Manchester, UK
| | - Christian Moulsdale
- Department of Physics and Astronomy, University of Manchester, Manchester, UK
- National Graphene Institute, University of Manchester, Manchester, UK
| | - V V Enaldiev
- Department of Physics and Astronomy, University of Manchester, Manchester, UK
- National Graphene Institute, University of Manchester, Manchester, UK
| | - J R Prance
- Department of Physics, Lancaster University, Lancaster, UK
| | - F H L Koppens
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, Spain
| | - R V Gorbachev
- Department of Physics and Astronomy, University of Manchester, Manchester, UK
- National Graphene Institute, University of Manchester, Manchester, UK
| | - K Watanabe
- National Institute for Materials Science, Tsukuba, Japan
| | - T Taniguchi
- National Institute for Materials Science, Tsukuba, Japan
| | - L I Glazman
- Department of Physics, Yale University, New Haven, CT, USA
| | - I V Grigorieva
- Department of Physics and Astronomy, University of Manchester, Manchester, UK
- National Graphene Institute, University of Manchester, Manchester, UK
| | - V I Fal'ko
- Department of Physics and Astronomy, University of Manchester, Manchester, UK
- National Graphene Institute, University of Manchester, Manchester, UK
- Henry Royce Institute for Advanced Materials, University of Manchester, Manchester, UK
| | - A K Geim
- Department of Physics and Astronomy, University of Manchester, Manchester, UK.
- National Graphene Institute, University of Manchester, Manchester, UK.
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Alexeev EM, Mullin N, Ares P, Nevison-Andrews H, Skrypka O, Godde T, Kozikov A, Hague L, Wang Y, Novoselov KS, Fumagalli L, Hobbs JK, Tartakovskii AI. Emergence of Highly Linearly Polarized Interlayer Exciton Emission in MoSe 2/WSe 2 Heterobilayers with Transfer-Induced Layer Corrugation. ACS Nano 2020; 14:11110-11119. [PMID: 32803959 DOI: 10.1021/acsnano.0c01146] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The availability of accessible fabrication methods based on deterministic transfer of atomically thin crystals has been essential for the rapid expansion of research into van der Waals heterostructures. An inherent issue of these techniques is the deformation of the polymer carrier film during the transfer, which can lead to highly nonuniform strain induced in the transferred two-dimensional material. Here, using a combination of optical spectroscopy, atomic force, and Kelvin probe force microscopy, we show that the presence of nanometer scale wrinkles formed due to transfer-induced stress relaxation can lead to strong changes in the optical properties of MoSe2/WSe2 heterostructures and the emergence of linearly polarized interlayer exciton photoluminescence. We attribute these changes to local breaking of crystal symmetry in the nanowrinkles, which act as efficient accumulation centers for interlayer excitons due to the strain-induced interlayer band gap reduction. Surface potential images of the rippled heterobilayer samples acquired using Kelvin probe force microscopy reveal variations of the local work function consistent with strain-induced band gap modulation, while the potential offset observed at the ridges of the wrinkles shows a clear correlation with the value of the tensile strain estimated from the wrinkle geometry. Our findings highlight the important role of the residual strain in defining optical properties of van der Waals heterostructures and suggest effective approaches for interlayer exciton manipulation by local strain engineering.
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Affiliation(s)
- Evgeny M Alexeev
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, United Kingdom
| | - Nic Mullin
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, United Kingdom
| | - Pablo Ares
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
- National Graphene Institute, University of Manchester, Booth Street East, Manchester M13 9PL, United Kingdom
| | - Harriet Nevison-Andrews
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
- National Graphene Institute, University of Manchester, Booth Street East, Manchester M13 9PL, United Kingdom
| | - Oleksandr Skrypka
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, United Kingdom
| | - Tillmann Godde
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, United Kingdom
| | - Aleksey Kozikov
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
- National Graphene Institute, University of Manchester, Booth Street East, Manchester M13 9PL, United Kingdom
| | - Lee Hague
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
- National Graphene Institute, University of Manchester, Booth Street East, Manchester M13 9PL, United Kingdom
| | - Yibo Wang
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
- National Graphene Institute, University of Manchester, Booth Street East, Manchester M13 9PL, United Kingdom
| | - Kostya S Novoselov
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
- National Graphene Institute, University of Manchester, Booth Street East, Manchester M13 9PL, United Kingdom
- Centre for Advanced 2D Materials, National University of Singapore, 117546 Singapore
- Chongqing 2D Materials Institute, Liangjiang New Area, Chongqing, 400714 China
| | - Laura Fumagalli
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
- National Graphene Institute, University of Manchester, Booth Street East, Manchester M13 9PL, United Kingdom
| | - Jamie K Hobbs
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, United Kingdom
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4
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Mudd GW, Svatek SA, Hague L, Makarovsky O, Kudrynskyi ZR, Mellor CJ, Beton PH, Eaves L, Novoselov KS, Kovalyuk ZD, Vdovin EE, Marsden AJ, Wilson NR, Patanè A. High broad-band photoresponsivity of mechanically formed InSe-graphene van der Waals heterostructures. Adv Mater 2015; 27:3760-6. [PMID: 25981798 PMCID: PMC4768130 DOI: 10.1002/adma.201500889] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 04/21/2015] [Indexed: 05/21/2023]
Abstract
High broad-band photoresponsivity of mechanically formed InSe-graphene van der Waals heterostructures is achieved by exploiting the broad-band transparency of graphene, the direct bandgap of InSe, and the favorable band line up of InSe with graphene. The photoresponsivity exceeds that for other van der Waals heterostructures and the spectral response extends from the near-infrared to the visible spectrum.
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Affiliation(s)
- Garry W Mudd
- School of Physics and Astronomy, The University of Nottingham, Nottingham, NG7 2RD, UK
| | - Simon A Svatek
- School of Physics and Astronomy, The University of Nottingham, Nottingham, NG7 2RD, UK
| | - Lee Hague
- School of Physics & Astronomy, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Oleg Makarovsky
- School of Physics and Astronomy, The University of Nottingham, Nottingham, NG7 2RD, UK
| | - Zakhar R Kudrynskyi
- School of Physics and Astronomy, The University of Nottingham, Nottingham, NG7 2RD, UK
| | - Christopher J Mellor
- School of Physics and Astronomy, The University of Nottingham, Nottingham, NG7 2RD, UK
| | - Peter H Beton
- School of Physics and Astronomy, The University of Nottingham, Nottingham, NG7 2RD, UK
| | - Laurence Eaves
- School of Physics and Astronomy, The University of Nottingham, Nottingham, NG7 2RD, UK
| | - Kostya S Novoselov
- School of Physics & Astronomy, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Zakhar D Kovalyuk
- Institute for Problems of Materials Science, The National Academy of Sciences of Ukraine, Chernivtsi, 58001, Ukraine
| | - Evgeny E Vdovin
- School of Physics and Astronomy, The University of Nottingham, Nottingham, NG7 2RD, UK
- Institute of Microelectronics Technology RAS, Chernogolovka, 142432, Russia
| | - Alex J Marsden
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - Neil R Wilson
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - Amalia Patanè
- School of Physics and Astronomy, The University of Nottingham, Nottingham, NG7 2RD, UK
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Stansfield GL, Vanitha PV, Johnston HM, Fan D, AlQahtani H, Hague L, Grell M, Thomas PJ. Growth of nanocrystals and thin films at the water-oil interface. Philos Trans A Math Phys Eng Sci 2010; 368:4313-4330. [PMID: 20732889 DOI: 10.1098/rsta.2010.0132] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The use of the water-oil interface provides significant advantages in the synthesis of inorganic nanostructures. Employing the water-toluene interface, luminescent CdS nanocrystals have been obtained at a relatively modest temperature of 35 degrees C. The diameters of the particulates can be varied between 1.0 and 5.0 nm. In addition, we have devised a new method for transferring thin films at the water-toluene interface onto solid substrates. Using this method, thin films consisting of Au and Ag nanocrystals spread over very large areas (square centimetres) are obtained in a single step. These films are directly usable as ingredients of functional devices. We show this by constructing a working amine sensor based on films of Au nanocrystals. The materials obtained have been characterized by X-ray diffraction, scanning and transmission electron microscopy, absorption and emission spectroscopy and charge transport measurements.
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Affiliation(s)
- G L Stansfield
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK
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