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Li W, Liao L, Deng C, Lebudi C, Liu J, Wang S, Yi D, Wang L, Li JF, Li Q. Artificial Domain Patterning in Ultrathin Ferroelectric Films via Modifying the Surface Electrostatic Boundary Conditions. NANO LETTERS 2024. [PMID: 38619536 DOI: 10.1021/acs.nanolett.4c00479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Nanoscale spatially controlled modulation of the properties of ferroelectrics via artificial domain pattering is crucial to their emerging optoelectronics applications. New patterning strategies to achieve high precision and efficiency and to link the resultant domain structures with device functionalities are being sought. Here, we present an epitaxial heterostructure of SrRuO3/PbTiO3/SrRuO3, wherein the domain configuration is delicately determined by the charge screening conditions in the SrRuO3 layer and the substrate strains. Chemical etching of the top SrRuO3 layer leads to a transition from in-plane a domains to out-of-plane c domains, accompanied by a giant (>105) modification in the second harmonic generation response. The modulation effect, coupled with the plasmonic resonance effect from SrRuO3, enables a highly flexible design of nonlinear optical devices, as demonstrated by a simulated split-ring resonator metasurface. This domain patterning strategy may be extended to more thin-film ferroelectric systems with domain stabilities amenable to electrostatic boundary conditions.
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Affiliation(s)
- Wei Li
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Lei Liao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chenguang Deng
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Collieus Lebudi
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Jingchun Liu
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Sixu Wang
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Di Yi
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Lifen Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jing-Feng Li
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Qian Li
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
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2
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Sarott MF, Müller MJ, Lehmann J, Burgat BJ, Fiebig M, Trassin M. Reversible Optical Control of Polarization in Epitaxial Ferroelectric Thin Films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2312437. [PMID: 38341379 DOI: 10.1002/adma.202312437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/19/2024] [Indexed: 02/12/2024]
Abstract
Light is an effective tool to probe the polarization and domain distribution in ferroelectric materials passively, that is, non-invasively, for example, via optical second harmonic generation (SHG). With the emergence of oxide electronics, there is now a strong demand to expand the role of light toward active control of the polarization. In this work, optical control of the ferroelectric polarization is demonstrated in prototypical epitaxial PbZrx Ti1-x O3 (PZT)-based heterostructures. This is accomplished in three steps, using above-bandgap UV light, while tracking the response of the polarization with optical SHG. First, it is found that UV-light exposure induces a transient enhancement or suppression of the ferroelectric polarization in films with an upward- or downward-oriented polarization, respectively. This behavior is attributed to a modified charge screening driven by the separation of photoexcited charge carriers at the Schottky interface of the ferroelectric thin film. Second, by taking advantage of this optical handle on electrostatics, remanent optical poling from a pristine multi-domain into a single-domain configuration is accomplished. Third, via thermal annealing or engineered electrostatic boundary conditions, a complete reversibility of the optical poling is further achieved. Hence, this work paves the way for the all-optical control of the spontaneous polarization in ferroelectric thin films.
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Affiliation(s)
- Martin F Sarott
- Department of Materials, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Marvin J Müller
- Department of Materials, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Jannis Lehmann
- Department of Materials, ETH Zurich, CH-8093, Zurich, Switzerland
- Center for Emergent Matter Science (CEMS), RIKEN, Wako, Saitama, 351-0198, Japan
- Department of Physics, ETH Zurich, CH-8093, Zurich, Switzerland
| | | | - Manfred Fiebig
- Department of Materials, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Morgan Trassin
- Department of Materials, ETH Zurich, CH-8093, Zurich, Switzerland
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3
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Vogel A, Ruiz Caridad A, Nordlander J, Sarott MF, Meier QN, Erni R, Spaldin NA, Trassin M, Rossell MD. Origin of the Critical Thickness in Improper Ferroelectric Thin Films. ACS APPLIED MATERIALS & INTERFACES 2023; 15:18482-18492. [PMID: 36996320 DOI: 10.1021/acsami.3c00412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Improper ferroelectrics are expected to be more robust than conventional ferroelectrics against depolarizing field effects and to exhibit a much-desired absence of critical thickness. Recent studies, however, revealed the loss of ferroelectric response in epitaxial improper ferroelectric thin films. Here, we investigate improper ferroelectric hexagonal YMnO3 thin films and find that the polarization suppression, and hence functionality, in the thinner films is due to oxygen off-stoichiometry. We demonstrate that oxygen vacancies form on the film surfaces to provide the necessary charge to screen the large internal electric field resulting from the positively charged YMnO3 surface layers. Additionally, we show that by modifying the oxygen concentration of the films, the phase transition temperatures can be substantially tuned. We anticipate that our findings are also valid for other ferroelectric oxide films and emphasize the importance of controlling the oxygen content and cation oxidation states in ferroelectrics for their successful integration in nanoscale applications.
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Affiliation(s)
- Alexander Vogel
- Electron Microscopy Center, Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
- Department of Materials, Eidgenössische Technische Hochschule Zürich, 8092 Zürich, Switzerland
| | - Alicia Ruiz Caridad
- Electron Microscopy Center, Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Johanna Nordlander
- Department of Materials, Eidgenössische Technische Hochschule Zürich, 8092 Zürich, Switzerland
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Martin F Sarott
- Department of Materials, Eidgenössische Technische Hochschule Zürich, 8092 Zürich, Switzerland
| | - Quintin N Meier
- Université Grenoble Alpes, CNRS, Institut Néel, 38042 Grenoble, France
| | - Rolf Erni
- Electron Microscopy Center, Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Nicola A Spaldin
- Department of Materials, Eidgenössische Technische Hochschule Zürich, 8092 Zürich, Switzerland
| | - Morgan Trassin
- Department of Materials, Eidgenössische Technische Hochschule Zürich, 8092 Zürich, Switzerland
| | - Marta D Rossell
- Electron Microscopy Center, Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
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4
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Huxter WS, Sarott MF, Trassin M, Degen CL. Imaging ferroelectric domains with a single-spin scanning quantum sensor. NATURE PHYSICS 2023; 19:644-648. [PMID: 37205126 PMCID: PMC10185469 DOI: 10.1038/s41567-022-01921-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 12/14/2022] [Indexed: 05/21/2023]
Abstract
The ability to sensitively image electric fields is important for understanding many nanoelectronic phenomena, including charge accumulation at surfaces1 and interfaces2 and field distributions in active electronic devices3. A particularly exciting application is the visualization of domain patterns in ferroelectric and nanoferroic materials4,5, owing to their potential in computing and data storage6-8. Here, we use a scanning nitrogen-vacancy (NV) microscope, well known for its use in magnetometry9, to image domain patterns in piezoelectric (Pb[Zr0.2Ti0.8]O3) and improper ferroelectric (YMnO3) materials through their electric fields. Electric field detection is enabled by measuring the Stark shift of the NV spin10,11 using a gradiometric detection scheme12. Analysis of the electric field maps allows us to discriminate between different types of surface charge distributions, as well as to reconstruct maps of the three-dimensional electric field vector and charge density. The ability to measure both stray electric and magnetic fields9,13 under ambient conditions opens opportunities for the study of multiferroic and multifunctional materials and devices8,14.
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Affiliation(s)
| | | | - Morgan Trassin
- Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Christian L. Degen
- Department of Physics, ETH Zurich, Zurich, Switzerland
- Quantum Center, ETH Zurich, Zurich, Switzerland
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5
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Trassin M, Garcia V. Bringing some bulk into ferroelectric devices. NATURE MATERIALS 2022; 21:730-731. [PMID: 35618825 DOI: 10.1038/s41563-022-01267-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Affiliation(s)
- Morgan Trassin
- Department of Materials, ETH Zurich, Zurich, Switzerland.
| | - Vincent Garcia
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, Palaiseau, France.
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6
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Signatures of enhanced out-of-plane polarization in asymmetric BaTiO 3 superlattices integrated on silicon. Nat Commun 2022; 13:265. [PMID: 35017533 PMCID: PMC8752726 DOI: 10.1038/s41467-021-27898-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 12/17/2021] [Indexed: 11/30/2022] Open
Abstract
In order to bring the diverse functionalities of transition metal oxides into modern electronics, it is imperative to integrate oxide films with controllable properties onto the silicon platform. Here, we present asymmetric LaMnO3/BaTiO3/SrTiO3 superlattices fabricated on silicon with layer thickness control at the unit-cell level. By harnessing the coherent strain between the constituent layers, we overcome the biaxial thermal tension from silicon and stabilize c-axis oriented BaTiO3 layers with substantially enhanced tetragonality, as revealed by atomically resolved scanning transmission electron microscopy. Optical second harmonic generation measurements signify a predominant out-of-plane polarized state with strongly enhanced net polarization in the tricolor superlattices, as compared to the BaTiO3 single film and conventional BaTiO3/SrTiO3 superlattice grown on silicon. Meanwhile, this coherent strain in turn suppresses the magnetism of LaMnO3 as the thickness of BaTiO3 increases. Our study raises the prospect of designing artificial oxide superlattices on silicon with tailored functionalities. Integrating multifunctional oxides on silicon is highly desirable. Here, the authors present asymmetric BaTiO3 superlattices on silicon exhibiting enhanced out-of-plane polarization by harnessing the interfacial strain and broken inversion symmetry.
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7
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Sarott MF, Gradauskaite E, Nordlander J, Strkalj N, Trassin M. In situmonitoring of epitaxial ferroelectric thin-film growth. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:293001. [PMID: 33873174 DOI: 10.1088/1361-648x/abf979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 04/19/2021] [Indexed: 06/12/2023]
Abstract
In ferroelectric thin films, the polarization state and the domain configuration define the macroscopic ferroelectric properties such as the switching dynamics. Engineering of the ferroelectric domain configuration during synthesis is in permanent evolution and can be achieved by a range of approaches, extending from epitaxial strain tuning over electrostatic environment control to the influence of interface atomic termination. Exotic polar states are now designed in the technologically relevant ultrathin regime. The promise of energy-efficient devices based on ultrathin ferroelectric films depends on the ability to create, probe, and manipulate polar states in ever more complex epitaxial architectures. Because most ferroelectric oxides exhibit ferroelectricity during the epitaxial deposition process, the direct access to the polarization emergence and its evolution during the growth process, beyond the realm of existing structuralin situdiagnostic tools, is becoming of paramount importance. We review the recent progress in the field of monitoring polar states with an emphasis on the non-invasive probes allowing investigations of polarization during the thin film growth of ferroelectric oxides. A particular importance is given to optical second harmonic generationin situ. The ability to determine the net polarization and domain configuration of ultrathin films and multilayers during the growth of multilayers brings new insights towards a better understanding of the physics of ultrathin ferroelectrics and further control of ferroelectric-based heterostructures for devices.
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Affiliation(s)
- Martin F Sarott
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Elzbieta Gradauskaite
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Johanna Nordlander
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Nives Strkalj
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Morgan Trassin
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
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8
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Spaldin NA, Efe I, Rossell MD, Gattinoni C. Layer and spontaneous polarizations in perovskite oxides and their interplay in multiferroic bismuth ferrite. J Chem Phys 2021; 154:154702. [PMID: 33887947 DOI: 10.1063/5.0046061] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We review the concept of surface charge, first, in the context of the polarization in ferroelectric materials and, second, in the context of layers of charged ions in ionic insulators. While the former is traditionally discussed in the ferroelectrics community and the latter in the surface science community, we remind the reader that the two descriptions are conveniently unified within the modern theory of polarization. In both cases, the surface charge leads to electrostatic instability-the so-called "polar catastrophe"-if it is not compensated, and we review the range of phenomena that arise as a result of different compensation mechanisms. We illustrate these concepts using the example of the prototypical multiferroic bismuth ferrite, BiFeO3, which is unusual in that its spontaneous ferroelectric polarization and the polarization arising from its layer charges can be of the same magnitude. As a result, for certain combinations of polarization orientation and surface termination, its surface charge is self-compensating. We use density functional calculations of BiFeO3 slabs and superlattices, analysis of high-resolution transmission electron micrographs, and examples from the literature to explore the consequences of this peculiarity.
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Affiliation(s)
- Nicola A Spaldin
- Department of Materials, ETH Zurich, CH-8093 Zürich, Switzerland
| | - Ipek Efe
- Department of Materials, ETH Zurich, CH-8093 Zürich, Switzerland
| | - Marta D Rossell
- Electron Microscopy Center, Swiss Federal Laboratories for Materials Science and Technology, Empa, 8600 Dübendorf, Switzerland
| | - Chiara Gattinoni
- Department of Materials, ETH Zurich, CH-8093 Zürich, Switzerland
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9
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Ye M, Hu S, Zhu Y, Zhang Y, Ke S, Xie L, Zhang Y, Hu S, Zhang D, Luo Z, Gu M, He J, Zhang P, Zhang W, Chen L. Electric Polarization Switching on an Atomically Thin Metallic Oxide. NANO LETTERS 2021; 21:144-150. [PMID: 33306405 DOI: 10.1021/acs.nanolett.0c03417] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Materials with reduced dimensions have been shown to host a wide variety of exotic properties and novel quantum states that often defy textbook wisdom. Polarization switching and metallic screening are well-known examples of mutually exclusive properties that cannot coexist in bulk solids. Here we report the fabrication of (SrRuO3)1/(BaTiO3)10 superlattices that exhibits reversible polarization switching in an atomically thin metallic layer. A multipronged investigation combining structural analyses, electrical measurements, and first-principles electronic structure calculations unravels the coexistence of two-dimensional (2D) metallicity in the SrRuO3 layer accompanied by the breaking of inversion symmetry, supporting electric polarization along the out-of-plane direction. Such a 2D ferroelectric-like metal paves a novel way to engineer a quantum multistate with unusual coexisting properties, such as ferroelectrics and metals, manipulated by external fields.
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Affiliation(s)
- Mao Ye
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Songbai Hu
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yuanmin Zhu
- Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, China
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yubo Zhang
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Shanming Ke
- School of Materials Science and Engineering, Nanchang University, Nanchang 330031, China
| | - Lin Xie
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yuan Zhang
- School of Materials Science and Engineering, Xiangtan University, Hunan 411105, China
| | - Sixia Hu
- Core Research Facilities, Southern University of Science and Technology, Shenzhen 518055, China
| | - Dongwen Zhang
- College of Science, National University of Defense Technology, Hunan 410073, China
| | - Zhenlin Luo
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China
| | - Meng Gu
- Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, China
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jiaqing He
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Peihong Zhang
- Department of Physics, State University of New York at Buffalo, Buffalo, New York 14260, United States
| | - Wenqing Zhang
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Lang Chen
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
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10
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Gradauskaite E, Meisenheimer P, Müller M, Heron J, Trassin M. Multiferroic heterostructures for spintronics. PHYSICAL SCIENCES REVIEWS 2020. [DOI: 10.1515/psr-2019-0072] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
AbstractFor next-generation technology, magnetic systems are of interest due to the natural ability to store information and, through spin transport, propagate this information for logic functions. Controlling the magnetization state through currents has proven energy inefficient. Multiferroic thin-film heterostructures, combining ferroelectric and ferromagnetic orders, hold promise for energy efficient electronics. The electric field control of magnetic order is expected to reduce energy dissipation by 2–3 orders of magnitude relative to the current state-of-the-art. The coupling between electrical and magnetic orders in multiferroic and magnetoelectric thin-film heterostructures relies on interfacial coupling though magnetic exchange or mechanical strain and the correlation between domains in adjacent functional ferroic layers. We review the recent developments in electrical control of magnetism through artificial magnetoelectric heterostructures, domain imprint, emergent physics and device paradigms for magnetoelectric logic, neuromorphic devices, and hybrid magnetoelectric/spin-current-based applications. Finally, we conclude with a discussion of experiments that probe the crucial dynamics of the magnetoelectric switching and optical tuning of ferroelectric states towards all-optical control of magnetoelectric switching events.
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Affiliation(s)
- Elzbieta Gradauskaite
- Department of Materials , ETH Zurich , Vladimir-Prelog-Weg 4 , Zurich , 8093 Switzerland
| | - Peter Meisenheimer
- Department of Materials Science and Engineering , University of Michigan , Ann Arbor , MI 48109 USA
| | - Marvin Müller
- Department of Materials , ETH Zurich , Vladimir-Prelog-Weg 4 , Zurich , 8093 Switzerland
| | - John Heron
- Department of Materials Science and Engineering , University of Michigan , Ann Arbor , MI 48109 USA
| | - Morgan Trassin
- Department of Materials , ETH Zurich , Vladimir-Prelog-Weg 4 , Zurich , 8093 Switzerland
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11
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Interface and surface stabilization of the polarization in ferroelectric thin films. Proc Natl Acad Sci U S A 2020; 117:28589-28595. [PMID: 33122429 PMCID: PMC7682414 DOI: 10.1073/pnas.2007736117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
With an ever-increasing societal demand for energy for electronic devices and in the face of the current climate issues, the need for low-energy-consuming electronics has never been greater. Ferroelectrics are promising energy-efficient device components for digital information storage, with the functionality relying on the manipulation of their polarization in ultrathin films. Polar discontinuities at the thin film interfaces and surfaces, however, can cause loss of polarization and thus functionality. Here we show how the interface and surface influence the overall polarization of the thin film. We show that the structure of the interface and surface can be tailored toward a specific polarization direction and strength, and that great control in the engineering of ferroelectrics thin films can be achieved. Ferroelectric perovskites present a switchable spontaneous polarization and are promising energy-efficient device components for digital information storage. Full control of the ferroelectric polarization in ultrathin films of ferroelectric perovskites needs to be achieved in order to apply this class of materials in modern devices. However, ferroelectricity itself is not well understood in this nanoscale form, where interface and surface effects become particularly relevant and where loss of net polarization is often observed. In this work, we show that the precise control of the structure of the top surface and bottom interface of the thin film is crucial toward this aim. We explore the properties of thin films of the prototypical ferroelectric lead titanate (PbTiO3) on a metallic strontium ruthenate (SrRuO3) buffer using a combination of computational (density functional theory) and experimental (optical second harmonic generation) methods. We find that the polarization direction and strength are influenced by chemical and electronic processes occurring at the epitaxial interface and at the surface. The polarization is particularly sensitive to adsorbates and to surface and interface defects. These results point to the possibility of controlling the polarization direction and magnitude by engineering specific interface and surface chemistries.
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12
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In-situ monitoring of interface proximity effects in ultrathin ferroelectrics. Nat Commun 2020; 11:5815. [PMID: 33199714 PMCID: PMC7669862 DOI: 10.1038/s41467-020-19635-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 10/25/2020] [Indexed: 01/28/2023] Open
Abstract
The development of energy-efficient nanoelectronics based on ferroelectrics is hampered by a notorious polarization loss in the ultrathin regime caused by the unscreened polar discontinuity at the interfaces. So far, engineering charge screening at either the bottom or the top interface has been used to optimize the polarization state. Yet, it is expected that the combined effect of both interfaces determines the final polarization state; in fact the more so the thinner a film is. The competition and cooperation between interfaces have, however, remained unexplored so far. Taking PbTiO3 as a model system, we observe drastic differences between the influence of a single interface and the competition and cooperation of two interfaces. We investigate the impact of these configurations on the PbTiO3 polarization when the interfaces are in close proximity, during thin-film synthesis in the ultrathin limit. By tailoring the interface chemistry towards a cooperative configuration, we stabilize a robust polarization state with giant polarization enhancement. Interface cooperation hence constitutes a powerful route for engineering the polarization in thin-film ferroelectrics towards improved integrability for oxide electronics in reduced dimension. How to maintain a robust polarization in ferroelectrics despite its inherent suppression when going to the thin-film limit is a long-standing issue. Here, the authors propose the concept of competitive and cooperative interfaces and establish robust polarization states in the ultrathin regime.
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13
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Sun Z, Huang H, Xun W, Shi S, Hao X, Ju S, Wu Y. First-principle study of sulfur vacancy and O 2adsorption on the electronic and optical properties of ferroelectric CuInP 2S 6monolayer. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:335001. [PMID: 32268301 DOI: 10.1088/1361-648x/ab87d0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 04/08/2020] [Indexed: 06/11/2023]
Abstract
Sulfur vacancy in MoS2has been found to have an important influence on the performance of optoelectronic devices. Here, we study the effect of sulfur vacancy and O2adsorption on the electronic and optical properties in the two-dimensional ferroelectric CuInP2S6. It is revealed that a defect state appears at the top of valence band with the presence of sulfur vacancy. However, when O2is chemisorbed at sulfur vacancy, the defect state disappears. The variation of charge state and charge transfer are calculated and discussed. Although the ferroelectricity is greatly suppressed with the presence of sulfur vacancy, the ferroelectric state can be recovered when the O2is adsorbed. Within the framework of GW + BSE method, the optical absorption edge of CuInP2S6monolayer exhibits a red-shift for the presence of sulfur vacancy and further O2adsorption gives rise to a blue-shift of the spectrum. Our findings have shown an effective way to improve the functionality of two-dimensional ferroelectrics via defect engineering.
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Affiliation(s)
- Zhizheng Sun
- Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application and School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009, People's Republic of China
| | - Hongfei Huang
- Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application and School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009, People's Republic of China
| | - Wei Xun
- School of Physical Science and Technology, Soochow University, Suzhou 215006, People's Republic of China
| | - Shanjin Shi
- Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application and School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009, People's Republic of China
| | - Xiang Hao
- Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application and School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009, People's Republic of China
| | - Sheng Ju
- School of Physical Science and Technology, Soochow University, Suzhou 215006, People's Republic of China
| | - Yinzhong Wu
- Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application and School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009, People's Republic of China
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14
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Estandía S, Sánchez F, Chisholm MF, Gázquez J. Rotational polarization nanotopologies in BaTiO 3/SrTiO 3 superlattices. NANOSCALE 2019; 11:21275-21283. [PMID: 31696194 DOI: 10.1039/c9nr08050c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ferroelectrics are characterized by domain structures as are other ferroics. At the nanoscale though, ferroelectrics may exhibit non-trivial or exotic polarization configurations under proper electrostatic and elastic conditions. These polar states may possess emerging properties not present in the bulk compounds and are promising for technological applications. Here, the observation of rotational polarization topologies at the nanoscale by means of aberration-corrected scanning transmission electron microscopy is reported in BaTiO3/SrTiO3 superlattices grown on cubic SrTiO3(001). The transition from a highly homogeneous polarization state to the formation of rotational nanodomains has been achieved by controlling the superlattice period while maintaining compressive clamping of the superlattice to the cubic SrTiO3 substrate. The nanodomains revealed in BaTiO3 prove that its nominal tetragonal structure also allows rotational polar textures.
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Affiliation(s)
- Saúl Estandía
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Barcelona, Spain.
| | - Florencio Sánchez
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Barcelona, Spain.
| | - Matthew F Chisholm
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Tennessee 37831-6064, USA
| | - Jaume Gázquez
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Barcelona, Spain.
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Strkalj N, Gradauskaite E, Nordlander J, Trassin M. Design and Manipulation of Ferroic Domains in Complex Oxide Heterostructures. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E3108. [PMID: 31554210 PMCID: PMC6803956 DOI: 10.3390/ma12193108] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 09/16/2019] [Accepted: 09/18/2019] [Indexed: 02/06/2023]
Abstract
The current burst of device concepts based on nanoscale domain-control in magnetically and electrically ordered systems motivates us to review the recent development in the design of domain engineered oxide heterostructures. The improved ability to design and control advanced ferroic domain architectures came hand in hand with major advances in investigation capacity of nanoscale ferroic states. The new avenues offered by prototypical multiferroic materials, in which electric and magnetic orders coexist, are expanding beyond the canonical low-energy-consuming electrical control of a net magnetization. Domain pattern inversion, for instance, holds promises of increased functionalities. In this review, we first describe the recent development in the creation of controlled ferroelectric and multiferroic domain architectures in thin films and multilayers. We then present techniques for probing the domain state with a particular focus on non-invasive tools allowing the determination of buried ferroic states. Finally, we discuss the switching events and their domain analysis, providing critical insight into the evolution of device concepts involving multiferroic thin films and heterostructures.
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Affiliation(s)
- Nives Strkalj
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland.
| | - Elzbieta Gradauskaite
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Johanna Nordlander
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Morgan Trassin
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland.
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