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Abramiuc LE, Tănase LC, Prieto MJ, de Souza Caldas L, Tiwari A, Apostol NG, Huşanu MA, Chirilă CF, Trupină L, Schmidt T, Pintilie L, Teodorescu CM. Surface charge dynamics on air-exposed ferroelectric Pb(Zr,Ti)O 3(001) thin films. NANOSCALE 2023; 15:13062-13075. [PMID: 37498343 DOI: 10.1039/d3nr02690f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
Probing of the free surface ferroelectric properties of thin polar films can be achieved either by estimating the band bending variance under the top-most layer or by studying the extent of the extrinsic charge accumulated outside the surface. Photoemitted or incoming low-energy electrons can be used to characterize locally both properties in a spectromicroscopic approach. Thin ferroelectric lead zirco-titanate (PZT) is investigated by combining low energy/mirror electron microscopy (LEEM/MEM) with photoemission electron microscopy (PEEM) and high-resolution photoelectron spectroscopy (XPS). Significant extrinsic negative compensation charge is proven to accumulate on the surface of the outward polarized thin film, indicated by high MEM-LEEM transition values, up to 15.3 eV, and is correlated with the surface electrostatic potential, which can be partially screened either by electrons interacting with the sample or by soft X-rays through the ejection of secondary electrons and generation of positive charge under the surface. A radiation-induced surface charge compensation effect is observed. The study indicates that air-exposed high quality ferroelectric thin films show large negative surface potentials, determined locally on the surface, which are nevertheless sensitive to beam damage and molecular desorption. These values represent a confirmation of previously estimated surface potential energy values determined from the LEED data on clean surfaces.
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Affiliation(s)
- Laura E Abramiuc
- National Institute of Materials Physics, Atomiştilor 405A, 077125 Măgurele-Ilfov, Romania.
| | - Liviu C Tănase
- Department of Interface Science, Fritz-Haber Institute of the Max Planck Society, 14195 Berlin, Germany
- National Institute of Materials Physics, Atomiştilor 405A, 077125 Măgurele-Ilfov, Romania.
| | - Mauricio J Prieto
- Department of Interface Science, Fritz-Haber Institute of the Max Planck Society, 14195 Berlin, Germany
| | - Lucas de Souza Caldas
- Department of Interface Science, Fritz-Haber Institute of the Max Planck Society, 14195 Berlin, Germany
| | - Aarti Tiwari
- Department of Interface Science, Fritz-Haber Institute of the Max Planck Society, 14195 Berlin, Germany
| | - Nicoleta G Apostol
- National Institute of Materials Physics, Atomiştilor 405A, 077125 Măgurele-Ilfov, Romania.
| | - Marius A Huşanu
- National Institute of Materials Physics, Atomiştilor 405A, 077125 Măgurele-Ilfov, Romania.
| | - Cristina F Chirilă
- National Institute of Materials Physics, Atomiştilor 405A, 077125 Măgurele-Ilfov, Romania.
| | - Lucian Trupină
- National Institute of Materials Physics, Atomiştilor 405A, 077125 Măgurele-Ilfov, Romania.
| | - Thomas Schmidt
- Department of Interface Science, Fritz-Haber Institute of the Max Planck Society, 14195 Berlin, Germany
| | - Lucian Pintilie
- National Institute of Materials Physics, Atomiştilor 405A, 077125 Măgurele-Ilfov, Romania.
| | - Cristian M Teodorescu
- National Institute of Materials Physics, Atomiştilor 405A, 077125 Măgurele-Ilfov, Romania.
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2
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Fuhrich A, Paier J, Tosoni S, Leandro Lewandowski A, Gura L, Schneider W, Pacchioni G, Freund H. Mixed Germania‐Silica Films on Ru(0001): A combined experimental and theoretical study. Isr J Chem 2023. [DOI: 10.1002/ijch.202300005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Affiliation(s)
- Alexander Fuhrich
- Fritz Haber Institute of the Max Planck Society 14195 Berlin Germany
| | - Joachim Paier
- Fritz Haber Institute of the Max Planck Society 14195 Berlin Germany
| | - Sergio Tosoni
- Accademia Nazionale dei Lincei Universita' degli Studi di Milano-Bicocca Dipartimento di Scienza dei Materiali 20125 Milano Italy
| | | | - Leonard Gura
- Fritz Haber Institute of the Max Planck Society 14195 Berlin Germany
| | | | - Gianfranco Pacchioni
- Accademia Nazionale dei Lincei Universita' degli Studi di Milano-Bicocca Dipartimento di Scienza dei Materiali 20125 Milano Italy
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3
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Roede ED, Shapovalov K, Moran TJ, Mosberg AB, Yan Z, Bourret E, Cano A, Huey BD, van Helvoort ATJ, Meier D. The Third Dimension of Ferroelectric Domain Walls. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2202614. [PMID: 35820118 DOI: 10.1002/adma.202202614] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 06/13/2022] [Indexed: 06/15/2023]
Abstract
Ferroelectric domain walls are quasi-2D systems that show great promise for the development of nonvolatile memory, memristor technology, and electronic components with ultrasmall feature size. Electric fields, for example, can change the domain wall orientation relative to the spontaneous polarization and switch between resistive and conductive states, controlling the electrical current. Being embedded in a 3D material, however, the domain walls are not perfectly flat and can form networks, which leads to complex physical structures. In this work, the importance of the nanoscale structure for the emergent transport properties is demonstrated, studying electronic conduction in the 3D network of neutral and charged domain walls in ErMnO3 . By combining tomographic microscopy techniques and finite element modeling, the contribution of domain walls within the bulk is clarified and the significance of curvature effects for the local conduction is shown down to the nanoscale. The findings provide insights into the propagation of electrical currents in domain wall networks, reveal additional degrees of freedom for their control, and provide quantitative guidelines for the design of domain-wall-based technology.
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Affiliation(s)
- Erik D Roede
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, Trondheim, 7491, Norway
| | - Konstantin Shapovalov
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra, 08193, Spain
| | - Thomas J Moran
- Department of Materials Science and Engineering, University of Connecticut, Storrs, CT, 06269, USA
| | - Aleksander B Mosberg
- Department of Physics, NTNU Norwegian University of Science and Technology, Trondheim, 7491, Norway
- SuperSTEM, STFC Daresbury Laboratories, Keckwick Lane, Warrington, WA4 4AD, UK
| | - Zewu Yan
- Department of Physics, ETH Zurich, Zürich, 8093, Switzerland
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Edith Bourret
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Andres Cano
- Universite Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France
| | - Bryan D Huey
- Department of Materials Science and Engineering, University of Connecticut, Storrs, CT, 06269, USA
| | | | - Dennis Meier
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, Trondheim, 7491, Norway
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4
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D’Olimpio G, Genuzio F, Menteş TO, Paolucci V, Kuo CN, Al Taleb A, Lue CS, Torelli P, Farías D, Locatelli A, Boukhvalov DW, Cantalini C, Politano A. Charge Redistribution Mechanisms in SnSe 2 Surfaces Exposed to Oxidative and Humid Environments and Their Related Influence on Chemical Sensing. J Phys Chem Lett 2020; 11:9003-9011. [PMID: 33035062 PMCID: PMC8015219 DOI: 10.1021/acs.jpclett.0c02616] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/01/2020] [Indexed: 06/11/2023]
Abstract
Tin diselenide (SnSe2) is a van der Waals semiconductor, which spontaneously forms a subnanometric SnO2 skin once exposed to air. Here, by means of surface-science spectroscopies and density functional theory, we have investigated the charge redistribution at the SnO2-SnSe2 heterojunction in both oxidative and humid environments. Explicitly, we find that the work function of the pristine SnSe2 surface increases by 0.23 and 0.40 eV upon exposure to O2 and air, respectively, with a charge transfer reaching 0.56 e-/SnO2 between the underlying SnSe2 and the SnO2 skin. Remarkably, both pristine SnSe2 and defective SnSe2 display chemical inertness toward water, in contrast to other metal chalcogenides. Conversely, the SnO2-SnSe2 interface formed upon surface oxidation is highly reactive toward water, with subsequent implications for SnSe2-based devices working in ambient humidity, including chemical sensors. Our findings also imply that recent reports on humidity sensing with SnSe2 should be reinterpreted, considering the pivotal role of the oxide skin in the interaction with water molecules.
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Affiliation(s)
- Gianluca D’Olimpio
- Department
of Physical and Chemical Sciences, University
of L’Aquila, via Vetoio, 67100 L’Aquila, AQ, Italy
| | - Francesca Genuzio
- Elettra-Sincrotrone
S.C.p.A., S.S. 14-km 163.5 in AREA Science Park, 34149 Trieste, Italy
| | - Tevfik Onur Menteş
- Elettra-Sincrotrone
S.C.p.A., S.S. 14-km 163.5 in AREA Science Park, 34149 Trieste, Italy
| | - Valentina Paolucci
- Department
of Industrial and Information Engineering and Economics, University of L’Aquila, Via G. Gronchi 18, I-67100 L’Aquila, Italy
| | - Chia-Nung Kuo
- Department
of Physics, National Cheng Kung University, 1 Ta-Hsueh Road, 70101 Tainan, Taiwan
| | - Amjad Al Taleb
- Departamento
de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Chin Shan Lue
- Department
of Physics, National Cheng Kung University, 1 Ta-Hsueh Road, 70101 Tainan, Taiwan
| | - Piero Torelli
- Elettra-Sincrotrone
S.C.p.A., S.S. 14-km 163.5 in AREA Science Park, 34149 Trieste, Italy
- Consiglio
Nazionale delle Ricerche (CNR)-Istituto Officina dei Materiali (IOM), Laboratorio TASC in Area Science
Park S.S. 14 km 163.5, 34149 Trieste, Italy
| | - Daniel Farías
- Departamento
de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Instituto
‘Nicolás Cabrera’, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Condensed
Matter Physics Center (IFIMAC), Universidad
Autónoma de Madrid, 28049 Madrid, Spain
| | - Andrea Locatelli
- Elettra-Sincrotrone
S.C.p.A., S.S. 14-km 163.5 in AREA Science Park, 34149 Trieste, Italy
| | - Danil W. Boukhvalov
- College
of Science, Institute of Materials Physics and Chemistry, Nanjing Forestry University, Nanjing 210037, P. R. China
- Theoretical
Physics and Applied Mathematics Department, Ural Federal University, Mira Street 19, 620002 Ekaterinburg, Russia
| | - Carlo Cantalini
- Department
of Industrial and Information Engineering and Economics, University of L’Aquila, Via G. Gronchi 18, I-67100 L’Aquila, Italy
| | - Antonio Politano
- Department
of Physical and Chemical Sciences, University
of L’Aquila, via Vetoio, 67100 L’Aquila, AQ, Italy
- CNR-IMM
Istituto per la Microelettronica e Microsistemi, VIII strada 5, I-95121 Catania, Italy
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5
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Quantifying work function differences using low-energy electron microscopy: The case of mixed-terminated strontium titanate. Ultramicroscopy 2019; 200:43-49. [PMID: 30822616 DOI: 10.1016/j.ultramic.2019.02.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 02/18/2019] [Indexed: 11/24/2022]
Abstract
For many applications, it is important to measure the local work function of a surface with high lateral resolution. Low-energy electron microscopy is regularly employed to this end since it is, in principle, very well suited as it combines high-resolution imaging with high sensitivity to local electrostatic potentials. For surfaces with areas of different work function, however, lateral electrostatic fields inevitably associated with work function discontinuities deflect the low-energy electrons and thereby cause artifacts near these discontinuities. We use ray-tracing simulations to show that these artifacts extend over hundreds of nanometers and cause an overestimation of the true work function difference near the discontinuity by a factor of 1.6 if the standard image analysis methods are used. We demonstrate on a mixed-terminated strontium titanate surface that comparing LEEM data with detailed ray-tracing simulations leads to much a more robust estimate of the work function difference.
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Zheng C, Yu L, Zhu L, Collins JL, Kim D, Lou Y, Xu C, Li M, Wei Z, Zhang Y, Edmonds MT, Li S, Seidel J, Zhu Y, Liu JZ, Tang WX, Fuhrer MS. Room temperature in-plane ferroelectricity in van der Waals In 2Se 3. SCIENCE ADVANCES 2018; 4:eaar7720. [PMID: 30027116 PMCID: PMC6044735 DOI: 10.1126/sciadv.aar7720] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 06/01/2018] [Indexed: 05/20/2023]
Abstract
Van der Waals (vdW) assembly of layered materials is a promising paradigm for creating electronic and optoelectronic devices with novel properties. Ferroelectricity in vdW layered materials could enable nonvolatile memory and low-power electronic and optoelectronic switches, but to date, few vdW ferroelectrics have been reported, and few in-plane vdW ferroelectrics are known. We report the discovery of in-plane ferroelectricity in a widely investigated vdW layered material, β'-In2Se3. The in-plane ferroelectricity is strongly tied to the formation of one-dimensional superstructures aligning along one of the threefold rotational symmetric directions of the hexagonal lattice in the c plane. Surprisingly, the superstructures and ferroelectricity are stable to 200°C in both bulk and thin exfoliated layers of In2Se3. Because of the in-plane nature of ferroelectricity, the domains exhibit a strong linear dichroism, enabling novel polarization-dependent optical properties.
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Affiliation(s)
- Changxi Zheng
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
- Monash Centre for Atomically Thin Materials, Monash University, Clayton, Victoria 3800, Australia
- Department of Civil Engineering, Monash University, Clayton, Victoria 3800, Australia
- Corresponding author. (C.Z.); (W.-X.T.); (M.S.F.)
| | - Lei Yu
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
| | - Lin Zhu
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
| | - James L. Collins
- Monash Centre for Atomically Thin Materials, Monash University, Clayton, Victoria 3800, Australia
- Australian Research Council (ARC) Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, Victoria 3800, Australia
- School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia
| | - Dohyung Kim
- School of Materials Science and Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Yaoding Lou
- Department of Mechanical Engineering, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Chao Xu
- Department of Applied Physics, Hong Kong Polytechnic University, Kowloon, Hong Kong SAR
| | - Meng Li
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
| | - Zheng Wei
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
| | - Yupeng Zhang
- College of Electronic Science and Technology, Shenzhen University, Shenzhen 518060, China
| | - Mark T. Edmonds
- Monash Centre for Atomically Thin Materials, Monash University, Clayton, Victoria 3800, Australia
- Australian Research Council (ARC) Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, Victoria 3800, Australia
- School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia
| | - Shiqiang Li
- Department of Electrical and Electronic Engineering, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Jan Seidel
- School of Materials Science and Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Ye Zhu
- Department of Applied Physics, Hong Kong Polytechnic University, Kowloon, Hong Kong SAR
| | - Jefferson Zhe Liu
- Department of Mechanical Engineering, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Wen-Xin Tang
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
- Corresponding author. (C.Z.); (W.-X.T.); (M.S.F.)
| | - Michael S. Fuhrer
- Monash Centre for Atomically Thin Materials, Monash University, Clayton, Victoria 3800, Australia
- Australian Research Council (ARC) Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, Victoria 3800, Australia
- School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia
- Corresponding author. (C.Z.); (W.-X.T.); (M.S.F.)
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7
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Nataf GF, Barrett N, Kreisel J, Guennou M. Raman signatures of ferroic domain walls captured by principal component analysis. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:035902. [PMID: 29091587 DOI: 10.1088/1361-648x/aa9778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Ferroic domain walls are currently investigated by several state-of-the art techniques in order to get a better understanding of their distinct, functional properties. Here, principal component analysis (PCA) of Raman maps is used to study ferroelectric domain walls (DWs) in LiNbO3 and ferroelastic DWs in NdGaO3. It is shown that PCA allows us to quickly and reliably identify small Raman peak variations at ferroelectric DWs and that the value of a peak shift can be deduced-accurately and without a priori-from a first order Taylor expansion of the spectra. The ability of PCA to separate the contribution of ferroelastic domains and DWs to Raman spectra is emphasized. More generally, our results provide a novel route for the statistical analysis of any property mapped across a DW.
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Affiliation(s)
- G F Nataf
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology, 41 Rue du Brill, L-4422 Belvaux, Luxembourg. SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France. Department of Materials Science, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
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Pawlik AS, Kämpfe T, Haußmann A, Woike T, Treske U, Knupfer M, Büchner B, Soergel E, Streubel R, Koitzsch A, Eng LM. Polarization driven conductance variations at charged ferroelectric domain walls. NANOSCALE 2017; 9:10933-10939. [PMID: 28731095 DOI: 10.1039/c7nr00217c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Conducting domain walls (CDWs) in ferroelectric materials are promising candidates for applications in a manifold of nanoscale, optoelectronic devices. Characterization of their microscopic properties, however, remains challenging due to their small dimension and highly insulating environment. Here, we inspect individual CDWs in single-crystalline LiNbO3 by the combination of photoemission electron microscopy (PEEM) and second harmonic generation (SHG) microscopy. While SHG unveils the overall domain wall inclination angle α, PEEM is sensitive to local conductance variations, both at and away from the domain wall. Thus, the two imaging techniques deliver complementary information over a large field of view. In agreement with earlier theoretical predictions we find that the local conductance is dictated by α and reveal a quantitative connection between them. Our results help to elucidate the electronic structure of CDWs and underline the value of PEEM as a non-contact characterization tool for mapping local conductance variations in highly resistive environments.
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Affiliation(s)
- A-S Pawlik
- IFW-Dresden, Helmholtzstr. 20, 01069 Dresden, Germany.
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