1
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He R, Xu H, Yang P, Chang K, Wang H, Zhong Z. Ferroelastic Twin-Wall-Mediated Ferroelectriclike Behavior and Bulk Photovoltaic Effect in SrTiO_{3}. PHYSICAL REVIEW LETTERS 2024; 132:176801. [PMID: 38728736 DOI: 10.1103/physrevlett.132.176801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 02/08/2024] [Accepted: 03/29/2024] [Indexed: 05/12/2024]
Abstract
Ferroelastic twin walls in nonpolar materials can give rise to a spontaneous polarization due to symmetry breaking. Nevertheless, the bistable polarity of twin walls and its reversal have not yet been demonstrated. Here, we report that the polarity of SrTiO_{3} twin walls can be switched by an ultralow strain gradient. Using first-principles-based machine-learning potential, we demonstrate that the twin walls can be deterministically rotated and realigned in specific directions under the strain gradient, which breaks the inversion symmetry of a sequence of walls and leads to a macroscopic polarization. The system can maintain polarity even after the constraint is removed. As a result, the polarization of twin walls can exhibit a ferroelectriclike hysteresis loop upon cyclic bending, namely flexoferroelectricity. Finally, we propose a scheme to experimentally detect the polarity of the twin wall by measuring the bulk photovoltaic responses. Our findings suggest a twin-wall-mediated flexoferroelectricity in SrTiO_{3}, which could be potentially exploited as functional elements in nanoelectronic devices design.
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Affiliation(s)
- Ri He
- Key Laboratory of Magnetic Materials Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Haowei Xu
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Peijun Yang
- Key Laboratory of Magnetic Materials Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Kai Chang
- Center for Quantum Matter, Zhejiang University, Hangzhou 310058, China
- School of Physics, Zhejiang University, Hangzhou 310058, China
| | - Hua Wang
- Center for Quantum Matter, Zhejiang University, Hangzhou 310058, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311215, China
- School of Physics, Zhejiang University, Hangzhou 310058, China
| | - Zhicheng Zhong
- Key Laboratory of Magnetic Materials Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Suzhou Institute for Advanced Research, University of Science and Technology of China, Suzhou 215123, China
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2
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Ding X, Jia Y, Gou G. Two-Dimensional Ferroelasticity and Domain-Wall Flexoelectricity in HgX 2 (X = Br or I) Monolayers. J Phys Chem Lett 2023; 14:420-429. [PMID: 36622322 DOI: 10.1021/acs.jpclett.2c03605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Electromechanical phenomena in two-dimensional (2D) materials can be related to sizable electric polarizations and switchable spontaneous ferroelasticity, allowing them to be used as miniaturized electronic and memory devices. Even in a parent centrosymmetric (nonpolar) ferroelastic (FE) material, non-zero polarization can be produced around the FE domain wall, owing to the strain-gradient-induced flexoelectricity. Compared with the negligibly weak flexoelectric effect in bulk compounds, significant electric polarizations can be expected in 2D FE materials that sustain a large elastic strain and a strain gradient. Using first-principles calculations, we predict that spontaneous 2D ferroelasticity and domain-wall flexoelectricity can be simultaneously realized in synthetic HgX2 (X = Br or I) monolayers. The FE phase renders three oriented variants, which form FE domain walls with a large strain gradient and the associated domain-wall flexoelectric polarizations. Our thermodynamic stability analysis and kinetic barrier simulations allow us to manipulate the domain-wall flexoelectricity via applied mechanical stress, thereby enabling future electromechanical applications in nanoelectronics.
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Affiliation(s)
- Xinkai Ding
- Frontier Institute of Science and Technology, and State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an710049, China
| | - Yinglu Jia
- Department of Chemistry and Department of Mechanical & Materials Engineering, University of Nebraska─Lincoln, Lincoln, Nebraska68588, United States
| | - Gaoyang Gou
- Frontier Institute of Science and Technology, and State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an710049, China
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3
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Talanov MV, Stash AI, Ivanov SA, Zhukova ES, Gorshunov BP, Nekrasov BM, Stolyarov VS, Kozlov VI, Savinov M, Bush AA. Octahedra-Tilted Control of Displacement Disorder and Dielectric Relaxation in Mn-Doped SrTiO 3 Single Crystals. J Phys Chem Lett 2022; 13:11720-11728. [PMID: 36512678 DOI: 10.1021/acs.jpclett.2c03513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Strontium titanate SrTiO3 (STO) is a canonical example of a quantum paraelectric, and its doping with manganese ions unlocks its potential as a quantum multiferroic candidate. However, to date, the specifics of incorporation of the manganese ion into the perovskite lattice and its impact on structure-property relationships are debatable questions. Herein, using high-precision X-ray diffraction of a Mn (2 atom %)-doped STO single crystal, clear fingerprints of the displacement disorder of Mn cations in the perovskite B-sublattice are observed. Moreover, near the temperature of the antiferrodistortive transition, the off-center Mn position splits in two, providing the unequal potential barrier's distribution for possible local atomic hopping. A link with this was found via analysis of the dielectric response that reveals two Arrhenius-type relaxation processes with similar activation energies (35 and 43 meV) and attempt frequencies (1 × 1011 and ∼1.6 × 1010 Hz), suggesting similar dielectric relaxation mechanisms.
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Affiliation(s)
- Mikhail V Talanov
- Research Institute of Physics, Southern Federal University, 194 Stachki av., 344090Rostov-on-Don, Russia
| | - Adam I Stash
- A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Science, 28 Vavilov Strasse, 119991Moscow, Russia
| | - Sergey A Ivanov
- Chemical Department, Moscow State University, 1 Leninskie Gory, 119991Moscow, Russia
| | - Elena S Zhukova
- Laboratory of Terahertz Spectroscopy, Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology (National Research University), 9 Institutskiy Pereulok, Dolgoprudny, Moscow Region141700, Russia
| | - Boris P Gorshunov
- Laboratory of Terahertz Spectroscopy, Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology (National Research University), 9 Institutskiy Pereulok, Dolgoprudny, Moscow Region141700, Russia
| | - Boris M Nekrasov
- Laboratory of Terahertz Spectroscopy, Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology (National Research University), 9 Institutskiy Pereulok, Dolgoprudny, Moscow Region141700, Russia
| | - Vasily S Stolyarov
- Center for Advanced Mesoscience and Nanotechnology, Moscow Institute of Physics and Technology (National Research University), 9 Institutskiy Pereulok, Dolgoprudny, Moscow Region141700, Russia
| | - Vladislav I Kozlov
- Research Institute of Solid-State Electronics Materials, MIREA - Russian Technological University (RTU MIREA), 78 Vernadsky prospect, 119454Moscow, Russia
- Kapitza Institute for Physical Problems RAS, 2 st. Kosygina, 119334Moscow, Russia
| | - Maxim Savinov
- Institute of Physics, Czech Academy of Sciences, 18200Prague 8, Czech Republic
| | - Alexander A Bush
- Research Institute of Solid-State Electronics Materials, MIREA - Russian Technological University (RTU MIREA), 78 Vernadsky prospect, 119454Moscow, Russia
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4
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Scott JJR, Casals B, Luo KF, Haq A, Mariotti D, Salje EKH, Arredondo M. Avalanche criticality in LaAlO[Formula: see text] and the effect of aspect ratio. Sci Rep 2022; 12:14818. [PMID: 36050337 PMCID: PMC9437108 DOI: 10.1038/s41598-022-18390-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 08/10/2022] [Indexed: 11/25/2022] Open
Abstract
Ferroic domain dynamics, as a function of external stimuli, can be collectively described as scale-invariant avalanches characterised by a critical exponent that are sensitive to the complexity of the domain microstructure. The understanding and manipulation of these avalanches lies at the heart of developing novel applications such as neuromorphic computing. Here we combine in situ heating optical observations and mean-field analysis to investigate the collective domain behaviour in pure-ferroelastic lanthanum aluminate (LaAlO[Formula: see text]) as a function of aspect ratio, the ratio of sample length to width, where the movement of the domains is predominantly driven by thermal stresses via thermal expansion/contraction during heat cycling. Our observations demonstrate that the aspect ratio induces (1) distinctive domain microstructures at room temperature, (2) a deviation of dynamical behaviour at high temperatures and (3) critical exponent mixing in the higher aspect ratio samples that accompanies this behaviour. While the critical exponents of each aspect ratio fall within mean-field predicted values, we highlight the effect that the aspect ratio has in inducing exponent mixing. Hence, furthering our understanding towards tuning and controlling avalanches which is crucial for fundamental and applied research.
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Affiliation(s)
- John J. R. Scott
- School of Mathematics and Physics, Queen’s University Belfast, Belfast, BT7 1NN Northern Ireland, UK
| | - Blai Casals
- Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ England, UK
| | - King-Fa Luo
- School of Mathematics and Physics, Queen’s University Belfast, Belfast, BT7 1NN Northern Ireland, UK
| | - Atta Haq
- School of Engineering, Ulster University, Jordanstown, BT37 0QB Northern Ireland, UK
| | - Davide Mariotti
- School of Engineering, Ulster University, Jordanstown, BT37 0QB Northern Ireland, UK
| | - Ekhard K. H. Salje
- Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ England, UK
| | - Miryam Arredondo
- School of Mathematics and Physics, Queen’s University Belfast, Belfast, BT7 1NN Northern Ireland, UK
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5
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Yue J, Ayino Y, Truttmann TK, Gastiasoro MN, Persky E, Khanukov A, Lee D, Thoutam LR, Kalisky B, Fernandes RM, Pribiag VS, Jalan B. Anomalous transport in high-mobility superconducting SrTiO 3 thin films. SCIENCE ADVANCES 2022; 8:eabl5668. [PMID: 35613270 PMCID: PMC9132441 DOI: 10.1126/sciadv.abl5668] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 04/08/2022] [Indexed: 06/15/2023]
Abstract
The study of subtle effects on transport in semiconductors requires high-quality epitaxial structures with low defect density. Using hybrid molecular beam epitaxy (MBE), SrTiO3 films with a low-temperature mobility exceeding 42,000 cm2 V-1 s-1 at a low carrier density of 3 × 1017 cm-3 were achieved. A sudden and sharp decrease in residual resistivity accompanied by an enhancement in the superconducting transition temperature were observed across the second Lifshitz transition where the third band becomes occupied, revealing dominant intraband scattering. These films further revealed an anomalous behavior in the Hall carrier density as a consequence of the antiferrodistortive (AFD) transition and the temperature dependence of the Hall scattering factor. Using hybrid MBE growth, phenomenological modeling, temperature-dependent transport measurements, and scanning superconducting quantum interference device imaging, we provide critical insights into the important role of inter- versus intraband scattering and of AFD domain walls on normal-state and superconducting properties of SrTiO3.
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Affiliation(s)
- Jin Yue
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA
| | - Yilikal Ayino
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA
| | - Tristan K. Truttmann
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA
| | - Maria N. Gastiasoro
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA
| | - Eylon Persky
- Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Alex Khanukov
- Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Dooyong Lee
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA
| | - Laxman R. Thoutam
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA
| | - Beena Kalisky
- Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Rafael M. Fernandes
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA
| | - Vlad S. Pribiag
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA
| | - Bharat Jalan
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA
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6
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Jakobsen VB, Trzop E, Dobbelaar E, Gavin LC, Chikara S, Ding X, Lee M, Esien K, Müller-Bunz H, Felton S, Collet E, Carpenter MA, Zapf VS, Morgan GG. Domain Wall Dynamics in a Ferroelastic Spin Crossover Complex with Giant Magnetoelectric Coupling. J Am Chem Soc 2021; 144:195-211. [PMID: 34939802 PMCID: PMC8759087 DOI: 10.1021/jacs.1c08214] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
![]()
Pinned and mobile
ferroelastic domain walls are detected in response
to mechanical stress in a Mn3+ complex with two-step thermal
switching between the spin triplet and spin quintet forms. Single-crystal
X-ray diffraction and resonant ultrasound spectroscopy on [MnIII(3,5-diCl-sal2(323))]BPh4 reveal three
distinct symmetry-breaking phase transitions in the polar space group
series Cc → Pc → P1 → P1(1/2). The transition mechanisms involve coupling between structural and
spin state order parameters, and the three transitions are Landau
tricritical, first order, and first order, respectively. The two first-order
phase transitions also show changes in magnetic properties and spin
state ordering in the Jahn–Teller-active Mn3+ complex.
On the basis of the change in symmetry from that of the parent structure, Cc, the triclinic phases are also ferroelastic, which has
been confirmed by resonant ultrasound spectroscopy. Measurements of
magnetoelectric coupling revealed significant changes in electric
polarization at both the Pc → P1 and P1 → P1(1/2) transitions, with opposite signs. All these phases are polar, while P1 is also chiral. Remanent electric polarization was detected
when applying a pulsed magnetic field of 60 T in the P1→ P1(1/2) region of bistability
at 90 K. Thus, we showcase here a rare example of multifunctionality
in a spin crossover material where the strain and polarization tensors
and structural and spin state order parameters are strongly coupled.
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Affiliation(s)
- Vibe Boel Jakobsen
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| | - Elzbieta Trzop
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes)-UMR 6251, F-35000 Rennes, France
| | - Emiel Dobbelaar
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| | - Laurence C Gavin
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| | - Shalinee Chikara
- Department of Physics, Auburn University Auburn, Alabama 36849, United States
| | - Xiaxin Ding
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Minseong Lee
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Kane Esien
- Centre for Nanostructured Media, School of Mathematics and Physics, Queen's University of Belfast, Belfast BT7 1NN, Northern Ireland, United Kingdom
| | - Helge Müller-Bunz
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| | - Solveig Felton
- Centre for Nanostructured Media, School of Mathematics and Physics, Queen's University of Belfast, Belfast BT7 1NN, Northern Ireland, United Kingdom
| | - Eric Collet
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes)-UMR 6251, F-35000 Rennes, France
| | - Michael A Carpenter
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, England, United Kingdom
| | - Vivien S Zapf
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Grace G Morgan
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
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7
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Low D, Ferguson GM, Jarjour A, Schaefer BT, Bachmann MD, Moll PJW, Nowack KC. Scanning SQUID microscopy in a cryogen-free dilution refrigerator. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:083704. [PMID: 34470407 DOI: 10.1063/5.0047652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 08/09/2021] [Indexed: 06/13/2023]
Abstract
We report a scanning superconducting quantum interference device (SQUID) microscope in a cryogen-free dilution refrigerator with a base temperature at the sample stage of at least 30 mK. The microscope is rigidly mounted to the mixing chamber plate to optimize thermal anchoring of the sample. The microscope housing fits into the bore of a superconducting vector magnet, and our design accommodates a large number of wires connecting the sample and sensor. Through a combination of vibration isolation in the cryostat and a rigid microscope housing, we achieve relative vibrations between the SQUID and the sample that allow us to image with micrometer resolution over a 150 µm range while the sample stage temperature remains at base temperature. To demonstrate the capabilities of our system, we show images acquired simultaneously of the static magnetic field, magnetic susceptibility, and magnetic fields produced by a current above a superconducting micrometer-scale device.
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Affiliation(s)
- D Low
- Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, New York 14853, USA
| | - G M Ferguson
- Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, New York 14853, USA
| | - Alexander Jarjour
- Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, New York 14853, USA
| | - Brian T Schaefer
- Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, New York 14853, USA
| | - Maja D Bachmann
- Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany
| | - Philip J W Moll
- Laboratory of Quantum Materials (QMAT), Institute of Materials, École Polytechnique Fédéral de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Katja C Nowack
- Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, New York 14853, USA
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8
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Krantz PW, Chandrasekhar V. Observation of Zero-Field Transverse Resistance in AlO_{x}/SrTiO_{3} Interface Devices. PHYSICAL REVIEW LETTERS 2021; 127:036801. [PMID: 34328768 DOI: 10.1103/physrevlett.127.036801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 06/10/2021] [Indexed: 06/13/2023]
Abstract
Domain walls in AlO_{x}/SrTiO_{3} (AlO_{x}/STO) interface devices at low temperatures give a rise to a new signature in the electrical transport of two-dimensional carrier gases formed at the surfaces or interfaces of STO-based heterostructures: a finite transverse resistance observed in Hall bars in zero external magnetic field. This transverse resistance depends on the local domain wall configuration and hence changes with temperature, gate voltage, thermal cycling, and position along the sample and can even change sign as a function of these parameters. The transverse resistance is observed below ≃70 K but grows and changes significantly below ≃40 K, the temperature at which the domain walls become increasingly polar. Surprisingly, the transverse resistance is much larger in (111) oriented heterostructures in comparison to (001) oriented heterostructures. Measurements of the capacitance between the conducting interface and an electrode applied to the substrate, which reflect the dielectric constant of the STO, indicate that this difference may be related to the greater variation of the temperature-dependent dielectric constant with electric field when the electric field is applied in the [111] direction. The finite transverse resistance can be explained inhomogeneous current flow due to the preferential transport of current along domain walls that are askew to the nominal direction of the injected current.
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Affiliation(s)
- P W Krantz
- Department of Physics, Northwestern University, Evanston, Illinois 60208, USA
| | - V Chandrasekhar
- Department of Physics, Northwestern University, Evanston, Illinois 60208, USA
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9
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Non-universal current flow near the metal-insulator transition in an oxide interface. Nat Commun 2021; 12:3311. [PMID: 34083533 PMCID: PMC8175561 DOI: 10.1038/s41467-021-23393-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 04/21/2021] [Indexed: 11/12/2022] Open
Abstract
In systems near phase transitions, macroscopic properties often follow algebraic scaling laws, determined by the dimensionality and the underlying symmetries of the system. The emergence of such universal scaling implies that microscopic details are irrelevant. Here, we locally investigate the scaling properties of the metal-insulator transition at the LaAlO3/SrTiO3 interface. We show that, by changing the dimensionality and the symmetries of the electronic system, coupling between structural and electronic properties prevents the universal behavior near the transition. By imaging the current flow in the system, we reveal that structural domain boundaries modify the filamentary flow close to the transition point, preventing a fractal with the expected universal dimension from forming. Macroscopic properties usually follow algebraic scaling laws near phase transitions. Here, the authors investigate the scaling properties of the metal‐insulator transition at the LaAlO3/SrTiO3 interface, finding that coupling between structural and electronic properties prevents the universal behavior.
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10
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Chen S, Chen X, Duijnstee EA, Sanyal B, Banerjee T. Unveiling Temperature-Induced Structural Domains and Movement of Oxygen Vacancies in SrTiO 3 with Graphene. ACS APPLIED MATERIALS & INTERFACES 2020; 12:52915-52921. [PMID: 33175485 PMCID: PMC7705893 DOI: 10.1021/acsami.0c15458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 11/03/2020] [Indexed: 06/11/2023]
Abstract
Heterointerfaces coupling complex oxides exhibit coexisting functional properties such as magnetism, superconductivity, and ferroelectricity, often absent in their individual constituent. SrTiO3 (STO), a canonical band insulator, is an active constituent of such heterointerfaces. Temperature-, strain-, or mechanical stress-induced ferroelastic transition leads to the formation of narrow domains and domain walls in STO. Such ferroelastic domain walls have been studied using imaging or transport techniques and, often, the findings are influenced by the choice and interaction of the electrodes with STO. In this work, we use graphene as a unique platform to unveil the movement of oxygen vacancies and ferroelastic domain walls near the STO surface by studying the temperature and gate bias dependence of charge transport in graphene. By sweeping the back gate voltage, we observe antihysteresis in graphene typically observed in conventional ferroelectric oxides. Interestingly, we find features in antihysteresis that are related to the movement of domain walls and of oxygen vacancies in STO. We ascertain this by analyzing the time dependence of the graphene square resistance at different temperatures and gate bias. Density functional calculations estimate the surface polarization and formation energies of layer-dependent oxygen vacancies in STO. This corroborates quantitatively with the activation energies determined from the temperature dependence of the graphene square resistance. Introduction of a hexagonal boron nitride (hBN) layer, of varying thicknesses, between graphene and STO leads to a gradual disappearance of the observed features, implying the influence of the domain walls onto the potential landscape in graphene.
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Affiliation(s)
- Si Chen
- Zernike
Institute for Advanced Materials, University
of Groningen, 9747 AG Groningen, The Netherlands
| | - Xin Chen
- Department
of Physics and Astronomy, Uppsala University, P.O. Box 516, 751 20 Uppsala, Sweden
| | - Elisabeth A. Duijnstee
- Zernike
Institute for Advanced Materials, University
of Groningen, 9747 AG Groningen, The Netherlands
| | - Biplab Sanyal
- Department
of Physics and Astronomy, Uppsala University, P.O. Box 516, 751 20 Uppsala, Sweden
| | - Tamalika Banerjee
- Zernike
Institute for Advanced Materials, University
of Groningen, 9747 AG Groningen, The Netherlands
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11
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Lebedev N, Stehno M, Rana A, Gauquelin N, Verbeeck J, Brinkman A, Aarts J. Inhomogeneous superconductivity and quasilinear magnetoresistance at amorphous LaTiO 3/SrTiO 3 interfaces. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 33:055001. [PMID: 33169729 DOI: 10.1088/1361-648x/abc102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We have studied the transport properties of LaTiO3/SrTiO3 (LTO/STO) heterostructures. In spite of 2D growth observed in reflection high energy electron diffraction, transmission electron microscopy images revealed that the samples tend to amorphize. Still, we observe that the structures are conducting, and some of them exhibit high conductance and/or superconductivity. We established that conductivity arises mainly on the STO side of the interface, and shows all the signs of the two-dimensional electron gas usually observed at interfaces between STO and LTO or LaAlO3, including the presence of two electron bands and tunability with a gate voltage. Analysis of magnetoresistance (MR) and superconductivity indicates the presence of spatial fluctuations of the electronic properties in our samples. That can explain the observed quasilinear out-of-plane MR, as well as various features of the in-plane MR and the observed superconductivity.
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Affiliation(s)
- N Lebedev
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
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12
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Fan S, Das H, Rébola A, Smith KA, Mundy J, Brooks C, Holtz ME, Muller DA, Fennie CJ, Ramesh R, Schlom DG, McGill S, Musfeldt JL. Site-specific spectroscopic measurement of spin and charge in (LuFeO 3) m/(LuFe 2O 4) 1 multiferroic superlattices. Nat Commun 2020; 11:5582. [PMID: 33149138 PMCID: PMC7642375 DOI: 10.1038/s41467-020-19285-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 10/07/2020] [Indexed: 11/09/2022] Open
Abstract
Interface materials offer a means to achieve electrical control of ferrimagnetism at room temperature as was recently demonstrated in (LuFeO3)m/(LuFe2O4)1 superlattices. A challenge to understanding the inner workings of these complex magnetoelectric multiferroics is the multitude of distinct Fe centres and their associated environments. This is because macroscopic techniques characterize average responses rather than the role of individual iron centres. Here, we combine optical absorption, magnetic circular dichroism and first-principles calculations to uncover the origin of high-temperature magnetism in these superlattices and the charge-ordering pattern in the m = 3 member. In a significant conceptual advance, interface spectra establish how Lu-layer distortion selectively enhances the Fe2+ → Fe3+ charge-transfer contribution in the spin-up channel, strengthens the exchange interactions and increases the Curie temperature. Comparison of predicted and measured spectra also identifies a non-polar charge ordering arrangement in the LuFe2O4 layer. This site-specific spectroscopic approach opens the door to understanding engineered materials with multiple metal centres and strong entanglement.
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Affiliation(s)
- Shiyu Fan
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, USA
| | - Hena Das
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
- Laboratory for Materials and Structures, Tokyo Institute of Technology, Midori-ku, 4259 Nagatesuta, Yokohama, Kanagawa, 226-8503, Japan
- Tokyo Tech World Research Hub Initiative, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa, 226-8503, Japan
| | - Alejandro Rébola
- Instituto de Física Rosario-CONICET, Boulevard 27 de Febrero 210 bis, 2000, Rosario, Argentina
| | - Kevin A Smith
- Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA
| | - Julia Mundy
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA
| | - Charles Brooks
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - Megan E Holtz
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - David A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, 14853, USA
| | - Craig J Fennie
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Darrell G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, 14853, USA
| | - Stephen McGill
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Janice L Musfeldt
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, USA.
- Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA.
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13
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Yun S, Song K, Chu K, Hwang SY, Kim GY, Seo J, Woo CS, Choi SY, Yang CH. Flexopiezoelectricity at ferroelastic domain walls in WO 3 films. Nat Commun 2020; 11:4898. [PMID: 32994411 PMCID: PMC7524836 DOI: 10.1038/s41467-020-18644-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 09/03/2020] [Indexed: 11/18/2022] Open
Abstract
The emergence of a domain wall property that is forbidden by symmetry in bulk can offer unforeseen opportunities for nanoscale low-dimensional functionalities in ferroic materials. Here, we report that the piezoelectric response is greatly enhanced in the ferroelastic domain walls of centrosymmetric tungsten trioxide thin films due to a large strain gradient of 106 m−1, which exists over a rather wide width (~20 nm) of the wall. The interrelationship between the strain gradient, electric polarity, and the electromechanical property is scrutinized by detecting of the lattice distortion using atomic scale strain analysis, and also by detecting the depolarized electric field using differential phase contrast technique. We further demonstrate that the domain walls can be manipulated and aligned in specific directions deterministically using a scanning tip, which produces a surficial strain gradient. Our findings provide the comprehensive observation of a flexopiezoelectric phenomenon that is artificially controlled by externally induced strain gradients. Observation of a strain-gradient-induced piezoresponse at domain walls remains a challenge. Here, the authors find the piezoelectric response to be enhanced in the ferroelastic domain walls of centrosymmetric tungsten trioxide thin films due to a large strain gradient over a wide width of the wall.
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Affiliation(s)
- Shinhee Yun
- Department of Physics & Center for Lattice Defectronics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Kyung Song
- Department of Materials Analysis and Evaluation, Korea Institute of Materials Science (KIMS), Changwon, 51508, Republic of Korea
| | - Kanghyun Chu
- Department of Physics & Center for Lattice Defectronics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,Group for Ferroelectrics and Functional Oxides, Institute of Materials, Swiss Federal Institute of Technology in Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Soo-Yoon Hwang
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Gi-Yeop Kim
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Jeongdae Seo
- Department of Physics & Center for Lattice Defectronics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Chang-Su Woo
- Department of Physics & Center for Lattice Defectronics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Si-Young Choi
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
| | - Chan-Ho Yang
- Department of Physics & Center for Lattice Defectronics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea. .,KAIST Institute for the NanoCentury, KAIST, Daejeon, 34141, Republic of Korea.
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14
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Yin C, Smink AEM, Leermakers I, Tang LMK, Lebedev N, Zeitler U, van der Wiel WG, Hilgenkamp H, Aarts J. Electron Trapping Mechanism in LaAlO_{3}/SrTiO_{3} Heterostructures. PHYSICAL REVIEW LETTERS 2020; 124:017702. [PMID: 31976734 DOI: 10.1103/physrevlett.124.017702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 09/13/2019] [Indexed: 06/10/2023]
Abstract
In LaAlO_{3}/SrTiO_{3} heterostructures, a still poorly understood phenomenon is that of electron trapping in back-gating experiments. Here, by combining magnetotransport measurements and self-consistent Schrödinger-Poisson calculations, we obtain an empirical relation between the amount of trapped electrons and the gate voltage. The amount of trapped electrons decays exponentially away from the interface. However, contrary to earlier observations, we find that the Fermi level remains well within the quantum well. The enhanced trapping of electrons induced by the gate voltage can therefore not be explained by a thermal escape mechanism. Further gate sweeping experiments strengthen that conclusion. We propose a new mechanism which involves the electromigration and clustering of oxygen vacancies in SrTiO_{3} and argue that such electron trapping is a universal phenomenon in SrTiO_{3}-based two-dimensional electron systems.
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Affiliation(s)
- Chunhai Yin
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - Alexander E M Smink
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Inge Leermakers
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Lucas M K Tang
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Nikita Lebedev
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - Uli Zeitler
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Wilfred G van der Wiel
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Hans Hilgenkamp
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Jan Aarts
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
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15
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Ferroelectric switching in ferroelastic materials with rough surfaces. Sci Rep 2019; 9:15834. [PMID: 31676819 PMCID: PMC6825142 DOI: 10.1038/s41598-019-52240-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 10/05/2019] [Indexed: 11/08/2022] Open
Abstract
Electric switching of non-polar bulk crystals is shown to occur when domain walls are polar in ferroelastic materials and when rough surfaces with steps on an atomic scale promote domain switching. All domains emerging from surface nuclei possess polar domain walls. The progression of domains is then driven by the interaction of the electric field with the polarity of domain boundaries. In contrast, smooth surfaces with higher activation barriers prohibit effective domain nucleation. We demonstrate the existence of an electrically driven ferroelectric hysteresis loop in a non-ferroelectric, ferroelastic bulk material.
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16
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Luo W, Boselli M, Poumirol JM, Ardizzone I, Teyssier J, van der Marel D, Gariglio S, Triscone JM, Kuzmenko AB. High sensitivity variable-temperature infrared nanoscopy of conducting oxide interfaces. Nat Commun 2019; 10:2774. [PMID: 31235858 PMCID: PMC6591405 DOI: 10.1038/s41467-019-10672-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 05/21/2019] [Indexed: 11/09/2022] Open
Abstract
Probing the local transport properties of two-dimensional electron systems (2DES) confined at buried interfaces requires a non-invasive technique with a high spatial resolution operating in a broad temperature range. In this paper, we investigate the scattering-type scanning near field optical microscopy as a tool for studying the conducting LaAlO3/SrTiO3 interface from room temperature down to 6 K. We show that the near-field optical signal, in particular its phase component, is highly sensitive to the transport properties of the electron system present at the interface. Our modeling reveals that such sensitivity originates from the interaction of the AFM tip with coupled plasmon-phonon modes with a small penetration depth. The model allows us to quantitatively correlate changes in the optical signal with the variation of the 2DES transport properties induced by cooling and by electrostatic gating. To probe the spatial resolution of the technique, we image conducting nano-channels written in insulating heterostructures with a voltage-biased tip of an atomic force microscope.
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Affiliation(s)
- Weiwei Luo
- Department of Quantum Matter Physics, University of Geneva, Quai Ernest-Ansermet 24, 1211, Geneva, Switzerland
| | - Margherita Boselli
- Department of Quantum Matter Physics, University of Geneva, Quai Ernest-Ansermet 24, 1211, Geneva, Switzerland
| | - Jean-Marie Poumirol
- Department of Quantum Matter Physics, University of Geneva, Quai Ernest-Ansermet 24, 1211, Geneva, Switzerland
| | - Ivan Ardizzone
- Department of Quantum Matter Physics, University of Geneva, Quai Ernest-Ansermet 24, 1211, Geneva, Switzerland
| | - Jérémie Teyssier
- Department of Quantum Matter Physics, University of Geneva, Quai Ernest-Ansermet 24, 1211, Geneva, Switzerland
| | - Dirk van der Marel
- Department of Quantum Matter Physics, University of Geneva, Quai Ernest-Ansermet 24, 1211, Geneva, Switzerland
| | - Stefano Gariglio
- Department of Quantum Matter Physics, University of Geneva, Quai Ernest-Ansermet 24, 1211, Geneva, Switzerland
| | - Jean-Marc Triscone
- Department of Quantum Matter Physics, University of Geneva, Quai Ernest-Ansermet 24, 1211, Geneva, Switzerland
| | - Alexey B Kuzmenko
- Department of Quantum Matter Physics, University of Geneva, Quai Ernest-Ansermet 24, 1211, Geneva, Switzerland.
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17
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Shperber Y, Vardi N, Persky E, Wissberg S, Huber ME, Kalisky B. Scanning SQUID microscopy in a cryogen-free cooler. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:053702. [PMID: 31153251 DOI: 10.1063/1.5087060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 04/07/2019] [Indexed: 06/09/2023]
Abstract
Scanning superconducting quantum interference device (SQUID) microscopy is a powerful tool for investigating electronic states at surfaces and interfaces by mapping their magnetic signal. SQUID operation requires cryogenic temperatures, which are typically achieved by immersing the cryostat in liquid helium. Making a transition to cryogen free systems is desirable, but has been challenging, as electric noise and vibrations are increased in such systems. We report on the successful operation of a scanning SQUID microscope in a modified Montana Instruments cryogen-free cooler with a base temperature of 4.3 K. We demonstrate scanning SQUID measurements with flux noise performance comparable to a wet system and correlate the sensor-sample vibrations to the cryocooler operation frequencies. In addition, we demonstrate successful operation in a variety of SQUID operation modes, including mapping static magnetic fields, measurement of local susceptibility, and spatial mapping of current flow distribution.
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Affiliation(s)
- Yishai Shperber
- Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel
| | - Naor Vardi
- Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel
| | - Eylon Persky
- Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel
| | - Shai Wissberg
- Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel
| | - Martin E Huber
- Departments of Physics and Electrical Engineering, University of Colorado Denver, Denver, Colorado 80217, USA
| | - Beena Kalisky
- Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel
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18
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Dunnett K, Zhu JX, Spaldin NA, Juričić V, Balatsky AV. Dynamic Multiferroicity of a Ferroelectric Quantum Critical Point. PHYSICAL REVIEW LETTERS 2019; 122:057208. [PMID: 30822032 DOI: 10.1103/physrevlett.122.057208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Indexed: 06/09/2023]
Abstract
Quantum matter hosts a large variety of phases, some coexisting, some competing; when two or more orders occur together, they are often entangled and cannot be separated. Dynamical multiferroicity, where fluctuations of electric dipoles lead to magnetization, is an example where the two orders are impossible to disentangle. Here we demonstrate an elevated magnetic response of a ferroelectric near the ferroelectric quantum critical point (FE QCP), since magnetic fluctuations are entangled with ferroelectric fluctuations. We thus suggest that any ferroelectric quantum critical point is an inherent multiferroic quantum critical point. We calculate the magnetic susceptibility near the FE QCP and find a region with enhanced magnetic signatures near the FE QCP and controlled by the tuning parameter of the ferroelectric phase. The effect is small but observable-we propose quantum paraelectric strontium titanate as a candidate material where the magnitude of the induced magnetic moments can be ∼5×10^{-7} μ_{B} per unit cell near the FE QCP.
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Affiliation(s)
- K Dunnett
- Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden
| | - J-X Zhu
- T-4 and CINT, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - N A Spaldin
- Materials Theory, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zürich, Switzerland
| | - V Juričić
- Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden
| | - A V Balatsky
- Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, USA
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19
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Manca N, Bothner D, Monteiro AMRVL, Davidovikj D, Sağlam YG, Jenkins M, Gabay M, Steele GA, Caviglia AD. Bimodal Phase Diagram of the Superfluid Density in LaAlO_{3}/SrTiO_{3} Revealed by an Interfacial Waveguide Resonator. PHYSICAL REVIEW LETTERS 2019; 122:036801. [PMID: 30735404 DOI: 10.1103/physrevlett.122.036801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Indexed: 06/09/2023]
Abstract
We explore the superconducting phase diagram of the two-dimensional electron system at the LaAlO_{3}/SrTiO_{3} interface by monitoring the frequencies of the cavity modes of a coplanar waveguide resonator fabricated in the interface itself. We determine the phase diagram of the superconducting transition as a function of the temperature and electrostatic gating, finding that both the superfluid density and the transition temperature follow a dome shape but that the two are not monotonically related. The ground state of this two-dimensional electron system is interpreted as a Josephson junction array, where a transition from long- to short-range order occurs as a function of the electronic doping. The synergy between correlated oxides and superconducting circuits is revealed to be a promising route to investigate these exotic compounds, complementary to standard magnetotransport measurements.
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Affiliation(s)
- Nicola Manca
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - Daniel Bothner
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - Ana M R V L Monteiro
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - Dejan Davidovikj
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - Yildiz G Sağlam
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - Mark Jenkins
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - Marc Gabay
- Laboratoire de Physique des Solides, Universite Paris-Sud and CNRS, Batiment 510, 91450 Orsay, France
| | - Gary A Steele
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - Andrea D Caviglia
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
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20
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Pesquera D, Carpenter MA, Salje EKH. Glasslike Dynamics of Polar Domain Walls in Cryogenic SrTiO_{3}. PHYSICAL REVIEW LETTERS 2018; 121:235701. [PMID: 30576178 DOI: 10.1103/physrevlett.121.235701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Indexed: 06/09/2023]
Abstract
Polar and highly mobile domain walls in SrTiO_{3} move under electric and elastic fields. Two vastly different timescales dominate their dynamical behavior. The previously observed fast changes lead to anomalies near 40 K where the elastic moduli soften and the polarity of the walls becomes strong. Keeping the sample under isothermal conditions leads to a new and unexpected phenomenon: The softening vanishes over timescales of days while the piezoelectricity of the sample remains unchanged. The hardening follows glass dynamics below an onset at T^{*}≈40 K. The timescale of the hardening is strongly temperature dependent and can be followed experimentally down to 34 K when the relaxation is not completed within two days. The relaxation time of a stretched exponential decay increases exponentially with the decreasing temperature. This relaxation process follows similar dynamics after zero-field cooling and after applying or removing an electric field. The sluggish behavior is attributed to collective interactions of domain patterns following overdamped glass dynamics rather than ballistic dynamics.
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Affiliation(s)
- David Pesquera
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom
| | - Michael A Carpenter
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom
| | - Ekhard K H Salje
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom
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21
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Coak MJ, Haines CRS, Liu C, Jarvis DM, Littlewood PB, Saxena SS. Dielectric Response of Quantum Critical Ferroelectric as a Function of Pressure. Sci Rep 2018; 8:14936. [PMID: 30297803 PMCID: PMC6175889 DOI: 10.1038/s41598-018-33320-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 09/21/2018] [Indexed: 11/09/2022] Open
Abstract
In this work we report for the first time measurements of the dielectric loss of single-crystal SrTiO3 under the application of hydrostatic pressure up to 20 kbar and temperatures down to 200 mK which allow us to comment on the evolution of new fundamental material properties and their relationship with the recently discovered quantum critical phenomena in this material. The well known 18 K peak or shoulder was no longer observed after pressure was applied, even after subsequently removing it, suggesting it is associated with the twin walls formed at the 110 K cubic-tetragonal transition. The family of familiar peaks were all seen to increase in temperature linearly with pressure and the height of the 9.4 K peak was drastically suppressed by even the smallest pressures. This peak is discussed in the context of a postulated ferroelectric quantum critical point in SrTiO3 and the behaviour of its size linked to the position of this point on the recently established phase diagram.
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Affiliation(s)
- M J Coak
- Cavendish Laboratory, Cambridge University, J. J. Thomson Ave, Cambridge, CB3 0HE, UK. .,Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Republic of Korea. .,Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea.
| | - C R S Haines
- Cavendish Laboratory, Cambridge University, J. J. Thomson Ave, Cambridge, CB3 0HE, UK.
| | - C Liu
- Cavendish Laboratory, Cambridge University, J. J. Thomson Ave, Cambridge, CB3 0HE, UK
| | - D M Jarvis
- Cavendish Laboratory, Cambridge University, J. J. Thomson Ave, Cambridge, CB3 0HE, UK
| | - P B Littlewood
- Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois, 60439, United States.,James Franck Institute, University of Chicago, 929 E 57 St., Chicago, Illinois, 60637, USA
| | - S S Saxena
- Cavendish Laboratory, Cambridge University, J. J. Thomson Ave, Cambridge, CB3 0HE, UK. .,National University of Science and Technology " MISiS", Leninsky Prospekt 4, Moscow, 119049, Russia.
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22
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Persky E, Kalisky B. Scanning SQUID View of Oxide Interfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1706653. [PMID: 29718543 DOI: 10.1002/adma.201706653] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 02/18/2018] [Indexed: 06/08/2023]
Abstract
The emergence of states of matter in low-dimensional systems is one of the most intriguing topics in condensed matter physics. Interfaces between nonmagnetic, insulating oxides are found to give rise to surprising behaviors, such as metallic conductivity, superconductivity, and magnetism. Sensitive, noninvasive local characterization tools are essential for understanding the electronic and magnetic behavior of these systems. Here, the scanning superconducting quantum interference device (SQUID) technique for local magnetic imaging is described and its contribution to the field of oxide interfaces is reviewed.
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Affiliation(s)
- Eylon Persky
- Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, 5290002,, Israel
| | - Beena Kalisky
- Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, 5290002,, Israel
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23
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Zhang X, Hu J, Cao Y, Xie J, Jia W, Wang S, Jia D. Insights into Crystal Facets of Perovskite SrSnO 3 as High-Performance Photocatalysts toward Environmental Remediation. Chemistry 2018; 24:14111-14118. [PMID: 30101549 DOI: 10.1002/chem.201803244] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 08/05/2018] [Indexed: 01/09/2023]
Abstract
To gain in-depth insights into the relevant exposed crystal planes for the photocatalytic performance of perovskite-structured oxides, SrSnO3 nanocrystals with different microstructures were synthesized and their photocatalytic activity for the degradation of simulated dye was investigated. The as-obtained orthorhombic SrSnO3 nanorods with exposed {001} crystal planes showed higher photocatalytic activity for decomposing methylene blue than that of SrSnO3 nanoribbons with exposed {111} crystal planes. The surface atomic configurations revealed that the quantity of SnO2 overlayer on the {001} crystal facets is slightly greater than that on {111} crystal planes, which results in exposed {001} crystal facets of the SrSnO3 nanorods that can exhibit better activity in the photocatalytic process, due to fewer lattice defects, which act as traps for photogenerated charge carriers to decrease the recombination of photoexcited electrons and holes. This originated from narrowing of the crystal face distance and slight variation of the unit cell parameters; the crystallographic axis became shorter and the value of lattice strain became smaller. As a result, SrSnO3 nanocrystals exhibited different surface behavior under post-treatment conditions and exhibited variation in the photocatalytic properties. The findings reported herein highlight the importance of probing the properties of surface facets in the evaluation of the photocatalytic performance of ternary metal oxides.
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Affiliation(s)
- Xinhua Zhang
- Key Laboratory of Energy Materials ChemistryMinistry of EducationKey Laboratory of Advanced Functional Materials, Autonomous RegionInstitute of Applied ChemistryXinjiang University Urumqi Xinjiang 830046 P.R. China
| | - Jindou Hu
- Key Laboratory of Energy Materials ChemistryMinistry of EducationKey Laboratory of Advanced Functional Materials, Autonomous RegionInstitute of Applied ChemistryXinjiang University Urumqi Xinjiang 830046 P.R. China
| | - Yali Cao
- Key Laboratory of Energy Materials ChemistryMinistry of EducationKey Laboratory of Advanced Functional Materials, Autonomous RegionInstitute of Applied ChemistryXinjiang University Urumqi Xinjiang 830046 P.R. China
| | - Jing Xie
- Key Laboratory of Energy Materials ChemistryMinistry of EducationKey Laboratory of Advanced Functional Materials, Autonomous RegionInstitute of Applied ChemistryXinjiang University Urumqi Xinjiang 830046 P.R. China
| | - Wei Jia
- Key Laboratory of Energy Materials ChemistryMinistry of EducationKey Laboratory of Advanced Functional Materials, Autonomous RegionInstitute of Applied ChemistryXinjiang University Urumqi Xinjiang 830046 P.R. China
| | - Shiqiang Wang
- Key Laboratory of Energy Materials ChemistryMinistry of EducationKey Laboratory of Advanced Functional Materials, Autonomous RegionInstitute of Applied ChemistryXinjiang University Urumqi Xinjiang 830046 P.R. China
| | - Dianzeng Jia
- Key Laboratory of Energy Materials ChemistryMinistry of EducationKey Laboratory of Advanced Functional Materials, Autonomous RegionInstitute of Applied ChemistryXinjiang University Urumqi Xinjiang 830046 P.R. China
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24
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Casals B, Schiaffino A, Casiraghi A, Hämäläinen SJ, López González D, van Dijken S, Stengel M, Herranz G. Low-Temperature Dielectric Anisotropy Driven by an Antiferroelectric Mode in SrTiO_{3}. PHYSICAL REVIEW LETTERS 2018; 120:217601. [PMID: 29883130 DOI: 10.1103/physrevlett.120.217601] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 01/09/2018] [Indexed: 06/08/2023]
Abstract
Strontium titanate (SrTiO_{3}) is the quintessential material for oxide electronics. One of its hallmark features is the transition, driven by antiferrodistortive (AFD) lattice modes, from a cubic to a ferroelastic low-temperature phase. Here we investigate the evolution of the ferroelastic twin walls upon application of an electric field. Remarkably, we find that the dielectric anisotropy of tetragonal SrTiO_{3}, rather than the intrinsic domain wall polarity, is the main driving force for the motion of the twins. Based on a combined first-principles and Landau-theory analysis, we show that such anisotropy is dominated by a trilinear coupling between the polarization, the AFD lattice tilts, and a previously overlooked antiferroelectric (AFE) mode. We identify the latter AFE phonon with the so-called "R mode" at ∼440 cm^{-1}, which was previously detected in IR experiments, but whose microscopic nature was unknown.
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Affiliation(s)
- Blai Casals
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Catalonia, Spain
| | - Andrea Schiaffino
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Catalonia, Spain
| | - Arianna Casiraghi
- NanoSpin, Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, FI-00076 Aalto, Finland
| | - Sampo J Hämäläinen
- NanoSpin, Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, FI-00076 Aalto, Finland
| | - Diego López González
- NanoSpin, Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, FI-00076 Aalto, Finland
| | - Sebastiaan van Dijken
- NanoSpin, Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, FI-00076 Aalto, Finland
| | - Massimiliano Stengel
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Catalonia, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys, 23, 08010 Barcelona, Catalonia, Spain
| | - Gervasi Herranz
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Catalonia, Spain
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