1
|
Smyth R, Blandy JN, Yu Z, Liu S, Topping CV, Cassidy SJ, Smura CF, Woodruff DN, Manuel P, Bull CL, Funnell NP, Ridley CJ, McGrady JE, Clarke SJ. High- versus Low-Spin Ni 2+ in Elongated Octahedral Environments: Sr 2NiO 2Cu 2Se 2, Sr 2NiO 2Cu 2S 2, and Sr 2NiO 2Cu 2(Se 1-x S x ) 2. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2022; 34:9503-9516. [PMID: 36397836 PMCID: PMC9648177 DOI: 10.1021/acs.chemmater.2c02002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Sr2NiO2Cu2Se2, comprising alternating [Sr2NiO2]2+ and [Cu2Se2]2- layers, is reported. Powder neutron diffraction shows that the Ni2+ ions, which are in a highly elongated NiO4Se2 environment with D4h symmetry, adopt a high-spin configuration and carry localized magnetic moments which order antiferromagnetically below ∼160 K in a √2a × √2a × 2c expansion of the nuclear cell with an ordered moment of 1.31(2) μB per Ni2+ ion. The adoption of the high-spin configuration for this d 8 cation in a pseudo-square-planar ligand field is supported by consideration of the experimental bond lengths and the results of density functional theory (DFT) calculations. This is in contrast to the sulfide analogue Sr2NiO2Cu2S2, which, according to both experiment and DFT calculations, has a much more elongated ligand field, more consistent with the low-spin configuration commonly found for square-planar Ni2+, and accordingly, there is no evidence for magnetic moment on the Ni2+ ions. Examination of the solid solution Sr2NiO2Cu2(Se1-x S x )2 shows direct evidence from the evolution of the crystal structure and the magnetic ordering for the transition from high-spin selenide-rich compounds to low-spin sulfide-rich compounds as a function of composition. Compression of Sr2NiO2Cu2Se2 up to 7.2 GPa does not show any structural signature of a change in the spin state. Consideration of the experimental and computed Ni2+ coordination environments and their subtle changes as a function of temperature, in addition to transitions evident in the transport properties and magnetic susceptibilities in the end members, Sr2NiO2Cu2Se2 and Sr2NiO2Cu2S2, suggest that simple high-spin and low-spin models for Ni2+ may not be entirely appropriate and point to further complexities in these compounds.
Collapse
Affiliation(s)
- Robert
D. Smyth
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, OxfordOX1 3QR, U.K.
| | - Jack N. Blandy
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, OxfordOX1 3QR, U.K.
- Diamond
Light Source Ltd., Harwell Science and Innovation Campus, DidcotOX11 0DE, U.K.
| | - Ziyu Yu
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, OxfordOX1 3QR, U.K.
| | - Shuai Liu
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, OxfordOX1 3QR, U.K.
- College
of Chemistry and Chemical Engineering, Anhui
University, Hefei230601, People’s Republic
of China
| | - Craig V. Topping
- Clarendon
Laboratory, Department of Physics, University
of Oxford, Parks Road, OxfordOX1
3PU, U.K.
| | - Simon J. Cassidy
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, OxfordOX1 3QR, U.K.
| | - Catherine F. Smura
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, OxfordOX1 3QR, U.K.
| | - Daniel N. Woodruff
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, OxfordOX1 3QR, U.K.
| | - Pascal Manuel
- ISIS
Facility, Rutherford Appleton Laboratory, Harwell Oxford, DidcotOX1 10QX, U.K.
| | - Craig L. Bull
- ISIS
Facility, Rutherford Appleton Laboratory, Harwell Oxford, DidcotOX1 10QX, U.K.
- School
of
Chemistry, The University of Edinburgh, King’s Buildings, David Brewster
Road, EdinburghEH9 3FJ, U.K.
| | - Nicholas P. Funnell
- ISIS
Facility, Rutherford Appleton Laboratory, Harwell Oxford, DidcotOX1 10QX, U.K.
| | | | - John E. McGrady
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, OxfordOX1 3QR, U.K.
| | - Simon J. Clarke
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, OxfordOX1 3QR, U.K.
| |
Collapse
|
2
|
Zhang Z, Shao J, Jin F, Dai K, Li J, Lan D, Hua E, Han Y, Wei L, Cheng F, Ge B, Wang L, Zhao Y, Wu W. Uniaxial Strain and Hydrostatic Pressure Engineering of the Hidden Magnetism in La 1-xCa xMnO 3 (0 ≤ x ≤ 1/2) Thin Films. NANO LETTERS 2022; 22:7328-7335. [PMID: 36067249 DOI: 10.1021/acs.nanolett.2c01352] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Here, using various substrates, we demonstrate that the in-plane uniaxial strain engineering can enhance the Jahn-Teller distortions and promote selective orbital occupancy to induce an emergent antiferromagnetic insulating (AFI) phase at x = 1/3 of La1-xCaxMnO3. Such an AFI phase depends not only on the magnitude of epitaxial strain but also on the symmetry of the substrates. Using the large uniaxial strain imparted by DyScO3(001) substrate, the AFI ground state is achieved in a wide range of doping levels (0 ≤ x ≤ 1/2), leaving an extended AFI phase diagram. Moreover, it is found that hydrostatic pressure can tune the AFI phase back to a hidden ferromagnetic metallic phase, accompanied by the formation of accommodation strain. The coaction of the accommodation strain, uniaxial strain, and hydrostatic pressure produces complex phase competition and evolution, and the result may shed light on phase space control of other functional perovskites with the competing magnetic interactions.
Collapse
Affiliation(s)
- Zixun Zhang
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Jifeng Shao
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
| | - Feng Jin
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Kunjie Dai
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Jingyuan Li
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Da Lan
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Enda Hua
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Yuyan Han
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China
| | - Long Wei
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China
| | - Feng Cheng
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Binghui Ge
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Lingfei Wang
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Yue Zhao
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wenbin Wu
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| |
Collapse
|
3
|
|
4
|
Grain-Size-Induced Collapse of Variable Range Hopping and Promotion of Ferromagnetism in Manganite La0.5Ca0.5MnO3. CRYSTALS 2022. [DOI: 10.3390/cryst12050724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Among transition metal oxides, manganites have attracted significant attention because of colossal magnetoresistance (CMR)—a magnetic field-induced metal–insulator transition close to the Curie temperature. CMR is closely related to the ferromagnetic (FM) metallic phase which strongly competes with the antiferromagnetic (AFM) charge ordered (CO) phase, where conducting electrons localize and create a long range order giving rise to insulator-like behavior. One of the major open questions in manganites is the exact origin of this insulating behavior. Here we report a dc resistivity and magnetization study on manganite La1−xCaxMnO3 ceramic samples with different grain size, at the very boundary between CO/AFM insulating and FM metallic phases x=0.5. Clear signatures of variable range hopping (VRH) are discerned in resistivity, implying the disorder-induced (Anderson) localization of conducting electrons. A significant increase of disorder associated with the reduction in grain size, however, pushes the system in the opposite direction from the Anderson localization scenario, resulting in a drastic decrease of resistivity, collapse of the VRH, suppression of the CO/AFM phase and growth of an FM contribution. These contradictory results are interpreted within the standard core-shell model and recent theories of Anderson localization of interacting particles.
Collapse
|
5
|
Negi D, Singh D, Ahuja R, van Aken PA. Coexisting commensurate and incommensurate charge ordered phases in CoO. Sci Rep 2021; 11:19415. [PMID: 34593883 PMCID: PMC8484683 DOI: 10.1038/s41598-021-98739-6] [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: 05/05/2021] [Accepted: 09/13/2021] [Indexed: 02/08/2023] Open
Abstract
The subtle interplay of strong electronic correlations in a distorted crystal lattice often leads to the evolution of novel emergent functionalities in the strongly correlated materials (SCM). Here, we unravel such unprecedented commensurate (COM) and incommensurate (ICOM) charge ordered (CO) phases at room temperature in a simple transition-metal mono-oxide, namely CoO. The electron diffraction pattern unveils a COM ([Formula: see text]=[Formula: see text] and ICOM ([Formula: see text]) periodic lattice distortion. Transmission electron microscopy (TEM) captures unidirectional and bidirectional stripe patterns of charge density modulations. The widespread phase singularities in the phase-field of the order parameter (OP) affirms the abundant topological disorder. Using, density functional theory (DFT) calculations, we demystify the underlying electronic mechanism. The DFT study shows that a cation disordering ([Formula: see text]) stabilizes Jahn-Teller (JT) distortion and localized aliovalent [Formula: see text] states in CoO. Therefore, the lattice distortion accompanied with mixed valence states ([Formula: see text]) states introduces CO in CoO. Our findings offer an electronic paradigm to engineer CO to exploit the associated electronic functionalities in widely available transition-metal mono-oxides.
Collapse
Affiliation(s)
- Devendra Negi
- Stuttgart Center for Electron Microscopy, Max Planck Institute for Solid State Research, Heisenbergstr.1, 70569, Stuttgart, Germany.
| | - Deobrat Singh
- Condensed Matter Theory Group, Materials Theory Division, Department of Physics and Astronomy, Uppsala University, Box 516, 75120, Uppsala, Sweden
| | - Rajeev Ahuja
- Condensed Matter Theory Group, Materials Theory Division, Department of Physics and Astronomy, Uppsala University, Box 516, 75120, Uppsala, Sweden
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, Punjab, 140001, India
| | - Peter A van Aken
- Stuttgart Center for Electron Microscopy, Max Planck Institute for Solid State Research, Heisenbergstr.1, 70569, Stuttgart, Germany
| |
Collapse
|
6
|
Bianco E, Kourkoutis LF. Atomic-Resolution Cryogenic Scanning Transmission Electron Microscopy for Quantum Materials. Acc Chem Res 2021; 54:3277-3287. [PMID: 34415721 DOI: 10.1021/acs.accounts.1c00303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
ConspectusThe rich physics permeating the phase diagrams of quantum materials have commanded the attention of the solid-state chemistry, materials science, and condensed-matter physics communities, sparking immense research into quantum phase transitions including superconducting, ferroic, and charge-order transitions. Many of these transitions occur at low temperatures and involve electronic, magnetic, or lattice order, which emerges on the atomic to mesoscopic scales. The complex interplay of these states and the heterogeneity that arises due to competition and intertwining of phases, however, is not fully understood and requires probes that capture ordering over multiple length scales down to the local atomic symmetries. Advances in scanning transmission electron microscopy (STEM) have enabled atomic-resolution imaging as well as mapping of functional picometer-scale atomic displacements inside materials. In this Account, we discuss our group's work to expand the reach of atomic-resolution STEM to cryogenic temperatures (cryo-STEM) to study quantum materials with focus on charge-ordered systems.Charge-ordered phases, in which electrons as well as the atomic lattice form periodic patterns that lift the translational symmetries of the crystal, are not only intertwined with superconductivity but also underlie other exotic electronic phenomena such as colossal magnetoresistance and metal-insulator transitions. The periodic lattice distortions (PLDs) modulate the positions of the crystal's nuclei, which can be readily probed by electron microscopy. In a set of examples, we demonstrate cryo-STEM as a powerful technique for probing local order, nanometer-scale heterogeneities, and topological defects in charge-ordered manganites and in transition metal dichalcogenide charge density wave (CDW) systems.With the nearly commensurate-to-commensurate CDW transition upon cooling in 1T-TaS2, we show that nanoscale lattice textures in CDW phases can be revealed through direct imaging. These early atomic-resolution results, however, also highlighted the need for improvements in cryo-STEM imaging, which led to a push to advance data collection and analysis for direct spatial mapping and quantification of PLDs. By introducing an image registration algorithm developed specifically to accommodate fast, low signal-to-noise image acquisitions of crystalline lattices, we address previous limitations due to sample drift in cryo-STEM experiments. This has enabled subangstrom cryo-STEM imaging with sufficient signal-to-noise to reveal the low temperature structure of 1T'-TaTe2. Furthermore, it allows mapping and quantification of PLD atomic displacements in the charge-ordered manganites Bi0.35Sr0.18Ca0.47MnO3 and Nd0.5Sr0.5MnO3 with picometer precision at ∼95 K to resolve not only distinct ordered phases (i.e., site- and bond-centered charge order) but also their nanoscale coexistence within the same sample.Atomic-resolution cryo-STEM opens new opportunities for understanding the microscopic underpinnings of quantum phases. In this Account, we focus on spatial mapping of lattice degrees of freedom in phases that are present at temperatures down to liquid nitrogen. Further advances in instrumentation are needed to expand the temperature range and to also enable atomic-resolution measurements that rely on weaker signals such as electron energy loss spectroscopy (EELS) for probing of electronic structure or 4D-STEM approaches to map electric and magnetic fields.
Collapse
Affiliation(s)
- Elisabeth Bianco
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States
| | - Lena F. Kourkoutis
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, United States
| |
Collapse
|
7
|
El Baggari I, Baek DJ, Zachman MJ, Lu D, Hikita Y, Hwang HY, Nowadnick EA, Kourkoutis LF. Charge order textures induced by non-linear couplings in a half-doped manganite. Nat Commun 2021; 12:3747. [PMID: 34145244 PMCID: PMC8213702 DOI: 10.1038/s41467-021-24026-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 05/28/2021] [Indexed: 11/13/2022] Open
Abstract
The self-organization of strongly interacting electrons into superlattice structures underlies the properties of many quantum materials. How these electrons arrange within the superlattice dictates what symmetries are broken and what ground states are stabilized. Here we show that cryogenic scanning transmission electron microscopy (cryo-STEM) enables direct mapping of local symmetries and order at the intra-unit-cell level in the model charge-ordered system Nd1/2Sr1/2MnO3. In addition to imaging the prototypical site-centered charge order, we discover the nanoscale coexistence of an exotic intermediate state which mixes site and bond order and breaks inversion symmetry. We further show that nonlinear coupling of distinct lattice modes controls the selection between competing ground states. The results demonstrate the importance of lattice coupling for understanding and manipulating the character of electronic self-organization and that cryo-STEM can reveal local order in strongly correlated systems at the atomic scale. In this paper, the authors demonstrate that cryogenic scanning transmission electron microscopy allows for the direct mapping of the local arrangements and symmetries of electronic order, providing a useful method for studying strongly correlated systems. They show this using the example of Nd1/2Sr1/2MnO3, a model charge ordered material.
Collapse
Affiliation(s)
| | - David J Baek
- School of Electrical and Computer Engineering, Cornell University, Ithaca, NY, USA.,Intel Corp., Hillsboro, OR, USA
| | - Michael J Zachman
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA.,Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Di Lu
- Department of Physics, Stanford University, Stanford, CA, USA.,Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.,Materials Science and Engineering, Northwestern University, Evanston, IL, USA
| | - Yasuyuki Hikita
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.,Department of Applied Physics, Stanford University, Stanford, CA, USA
| | - Harold Y Hwang
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.,Department of Applied Physics, Stanford University, Stanford, CA, USA
| | - Elizabeth A Nowadnick
- Department of Materials Science and Engineering, University of California Merced, Merced, CA, USA
| | - Lena F Kourkoutis
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA. .,Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY, USA.
| |
Collapse
|
8
|
Shen Y, Fabbris G, Miao H, Cao Y, Meyers D, Mazzone DG, Assefa TA, Chen XM, Kisslinger K, Prabhakaran D, Boothroyd AT, Tranquada JM, Hu W, Barbour AM, Wilkins SB, Mazzoli C, Robinson IK, Dean MPM. Charge Condensation and Lattice Coupling Drives Stripe Formation in Nickelates. PHYSICAL REVIEW LETTERS 2021; 126:177601. [PMID: 33988428 DOI: 10.1103/physrevlett.126.177601] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 03/31/2021] [Indexed: 06/12/2023]
Abstract
Revealing the predominant driving force behind symmetry breaking in correlated materials is sometimes a formidable task due to the intertwined nature of different degrees of freedom. This is the case for La_{2-x}Sr_{x}NiO_{4+δ}, in which coupled incommensurate charge and spin stripes form at low temperatures. Here, we use resonant x-ray photon correlation spectroscopy to study the temporal stability and domain memory of the charge and spin stripes in La_{2-x}Sr_{x}NiO_{4+δ}. Although spin stripes are more spatially correlated, charge stripes maintain a better temporal stability against temperature change. More intriguingly, charge order shows robust domain memory with thermal cycling up to 250 K, far above the ordering temperature. These results demonstrate the pinning of charge stripes to the lattice and that charge condensation is the predominant factor in the formation of stripe orders in nickelates.
Collapse
Affiliation(s)
- Y Shen
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - G Fabbris
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - H Miao
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
- Material Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - Y Cao
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - D Meyers
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
- Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078, USA
| | - D G Mazzone
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - T A Assefa
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - X M Chen
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - K Kisslinger
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - D Prabhakaran
- Department of Physics, University of Oxford, Clarendon Laboratory, Oxford OX1 3PU, United Kingdom
| | - A T Boothroyd
- Department of Physics, University of Oxford, Clarendon Laboratory, Oxford OX1 3PU, United Kingdom
| | - J M Tranquada
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - W Hu
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - A M Barbour
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - S B Wilkins
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - C Mazzoli
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - I K Robinson
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - M P M Dean
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| |
Collapse
|
9
|
Jiang Y, Yuan L, Wang X, Zhang W, Liu J, Wu X, Huang K, Li Y, Liu Z, Feng S. Jahn-Teller Disproportionation Induced Exfoliation of Unit-Cell Scale ϵ-MnO 2. Angew Chem Int Ed Engl 2020; 59:22659-22666. [PMID: 32840953 DOI: 10.1002/anie.202010246] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 08/22/2020] [Indexed: 11/08/2022]
Abstract
Exfoliation of non-layered (structurally) bulk materials at the nanoscale is challenging because of the strong chemical bonds in the lattice, as opposed to the weak van der Waals (vdW) interactions in layered materials. We propose a top-down method to exfoliate ϵ-MnO2 nanosheets in a family of charge-ordered La1-x AEx MnO3 (AE=Ca, Sr, Ba) perovskites, taking advantage of the Jahn-Teller disproportionation effect of Mn3+ and bond-strength differences. ϵ-MnO2 crystallized into a nickel arsenide (NiAs) structure, with a thickness of 0.91 nm, displays thermal metastability and superior water oxidation activity compared to other manganese oxides. The exfoliation mechanism involves a synergistic proton-induced Mn3+ disproportionation and structural reconstruction. The synthetic method could also be potentially extended to the exfoliation of other two-dimensional nanosheet materials with non-layered structures.
Collapse
Affiliation(s)
- Yilan Jiang
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Long Yuan
- Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University, Changchun, 130103, P. R. China
| | - Xiyang Wang
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Wei Zhang
- Key Laboratory of Mobile Materials MOE, and Electron Microscopy Center, Jilin University, Changchun, 130012, P. R. China
| | - Jinghai Liu
- Inner Mongolia Key Laboratory of Carbon Nanomaterials, Nano Innovation Institute (NII), College of Chemistry and Chemical Engineering, Inner Mongolia University for Nationalities, Tongliao, 028000, P. R. China
| | - Xiaofeng Wu
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Keke Huang
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Yefei Li
- Collaborative Innovation Center of Chemistry for Energy Material, Key Laboratory of Computational Physical Science (Ministry of Education), Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, Shanghai, 200433, P. R. China
| | - Zhipan Liu
- Collaborative Innovation Center of Chemistry for Energy Material, Key Laboratory of Computational Physical Science (Ministry of Education), Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, Shanghai, 200433, P. R. China
| | - Shouhua Feng
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| |
Collapse
|
10
|
Jiang Y, Yuan L, Wang X, Zhang W, Liu J, Wu X, Huang K, Li Y, Liu Z, Feng S. Jahn–Teller Disproportionation Induced Exfoliation of Unit‐Cell Scale ϵ‐MnO
2. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202010246] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yilan Jiang
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry Jilin University Changchun 130012 P. R. China
| | - Long Yuan
- Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education Jilin Normal University Changchun 130103 P. R. China
| | - Xiyang Wang
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry Jilin University Changchun 130012 P. R. China
| | - Wei Zhang
- Key Laboratory of Mobile Materials MOE, and Electron Microscopy Center Jilin University Changchun 130012 P. R. China
| | - Jinghai Liu
- Inner Mongolia Key Laboratory of Carbon Nanomaterials Nano Innovation Institute (NII) College of Chemistry and Chemical Engineering Inner Mongolia University for Nationalities Tongliao 028000 P. R. China
| | - Xiaofeng Wu
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry Jilin University Changchun 130012 P. R. China
| | - Keke Huang
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry Jilin University Changchun 130012 P. R. China
| | - Yefei Li
- Collaborative Innovation Center of Chemistry for Energy Material Key Laboratory of Computational Physical Science (Ministry of Education) Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Department of Chemistry Fudan University Shanghai 200433 P. R. China
| | - Zhipan Liu
- Collaborative Innovation Center of Chemistry for Energy Material Key Laboratory of Computational Physical Science (Ministry of Education) Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Department of Chemistry Fudan University Shanghai 200433 P. R. China
| | - Shouhua Feng
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry Jilin University Changchun 130012 P. R. China
| |
Collapse
|
11
|
Frano A, Blanco-Canosa S, Keimer B, Birgeneau RJ. Charge ordering in superconducting copper oxides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:374005. [PMID: 31829986 DOI: 10.1088/1361-648x/ab6140] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 12/12/2019] [Indexed: 06/10/2023]
Abstract
Charge order has recently been identified as a leading competitor of high-temperature superconductivity in moderately doped cuprates. We provide a survey of universal and materials-specific aspects of this phenomenon, with emphasis on results obtained by scattering methods. In particular, we discuss the structure, periodicity, and stability range of the charge-ordered state, its response to various external perturbations, the influence of disorder, the coexistence and competition with superconductivity, as well as collective charge dynamics. In the context of this journal issue which honors Roger Cowley's legacy, we also discuss the connection of charge ordering with lattice vibrations and the central-peak phenomenon. We end the review with an outlook on research opportunities offered by new synthesis methods and experimental platforms, including cuprate thin films and superlattices.
Collapse
Affiliation(s)
- Alex Frano
- Department of Physics, University of California, San Diego, CA 92093, United States of America
| | - Santiago Blanco-Canosa
- Donostia International Physics Center, DIPC, 20018 Donostia-San Sebastian, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Basque Country, Spain
| | - Bernhard Keimer
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Robert J Birgeneau
- Department of Physics, University of California, Berkeley, CA 94720, United States of America
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA 94720, United States of America
| |
Collapse
|
12
|
Hong SS, Gu M, Verma M, Harbola V, Wang BY, Lu D, Vailionis A, Hikita Y, Pentcheva R, Rondinelli JM, Hwang HY. Extreme tensile strain states in La
0.7
Ca
0.3
MnO
3
membranes. Science 2020; 368:71-76. [DOI: 10.1126/science.aax9753] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 03/09/2020] [Indexed: 11/02/2022]
Affiliation(s)
- Seung Sae Hong
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Department of Materials Science and Engineering, University of California, Davis, CA 95616, USA
| | - Mingqiang Gu
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Manish Verma
- Department of Physics and Center for Nanointegration (CENIDE), University of Duisburg-Essen, 47053 Duisburg, Germany
| | - Varun Harbola
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - Bai Yang Wang
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - Di Lu
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - Arturas Vailionis
- Stanford Nano Shared Facilities, Stanford University, Stanford, CA 94305, USA
- Department of Physics, Kaunas University of Technology, LT-51368 Kaunas, Lithuania
| | - Yasuyuki Hikita
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Rossitza Pentcheva
- Department of Physics and Center for Nanointegration (CENIDE), University of Duisburg-Essen, 47053 Duisburg, Germany
| | - James M. Rondinelli
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Harold Y. Hwang
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| |
Collapse
|
13
|
Udalov OG, Beloborodov IS. Stripe structures in phase separated magnetic oxides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:415801. [PMID: 31261142 DOI: 10.1088/1361-648x/ab2e3e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We investigate the phase separated inhomogeneous charge and spin states in magnetic oxides. In particular, we study one dimensional harmonic waves and stripe structures. We show that harmonic spin charge waves are unstable and inevitably transform into two or three dimensional structures, while the stripe structures can be stable for certain parameters. Such stripe structures may allow the control of magnetic state with electric field in a magnetic oxide thin film.
Collapse
Affiliation(s)
- O G Udalov
- Department of Physics and Astronomy, California State University Northridge, Northridge, CA 91330, United States of America. Institute for Physics of Microstructures RAS, Nizhny Novgorod, 603950, Russia
| | | |
Collapse
|
14
|
Dudka AP, Khrykina ON, Bolotina NB, Shitsevalova NY. Jahn–Teller Lattice Distortions and Asymmetric Electron Density Distribution in the Structure of TmB12 Dodecaboride in the Temperature Range of 85–293 K. CRYSTALLOGR REP+ 2019. [DOI: 10.1134/s1063774519050079] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
15
|
Sluchanko NE, Azarevich AN, Bogach AV, Bolotina NB, Glushkov VV, Demishev SV, Dudka AP, Khrykina ON, Filipov VB, Shitsevalova NY, Komandin GA, Muratov AV, Aleshchenko YA, Zhukova ES, Gorshunov BP. Observation of dynamic charge stripes in Tm 0.19Yb 0.81B 12 at the metal-insulator transition. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:065604. [PMID: 30524111 DOI: 10.1088/1361-648x/aaf44e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Accurate low temperature charge transport measurements in combination with high-precision x-ray diffraction experiments have allowed detection of the symmetry lowering in the single domain Tm0.19Yb0.81B12 crystals that belong to the family of dodecaborides with metal-insulator transition. Based on the fine structure analysis we discover the formation of dynamic charge stripes within the semiconducting matrix of Tm0.19Yb0.81B12. The charge dynamics in these conducting nano-size channels is characterized by broad-band optical spectroscopy that allowed estimating the frequency (~2.4 × 1011 Hz) of quantum motion of the charge carriers. It is suggested that cooperative Jahn-Teller effect in the boron sublattice is a cause of the large-amplitude rattling modes of the Tm and Yb ions responsible for the 'modulation' of the conduction band along one of the [Formula: see text] directions through the variation of 5d-2p hybridization of electron states.
Collapse
Affiliation(s)
- N E Sluchanko
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Vavilov str. 38, Moscow 119991, Russia. Moscow Institute of Physics and Technology, 9, Institutskii per., Dolgoprudnyi, Moscow region 141700, Russia
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Gye G, Oh E, Yeom HW. Topological Landscape of Competing Charge Density Waves in 2H-NbSe_{2}. PHYSICAL REVIEW LETTERS 2019; 122:016403. [PMID: 31012648 DOI: 10.1103/physrevlett.122.016403] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Indexed: 06/09/2023]
Abstract
Despite decades of studies of the charge density wave (CDW) of 2H-NbSe_{2}, the origin of its incommensurate CDW ground state has not been understood. We discover that the CDW of 2H-NbSe_{2} is composed of two different, energetically competing, structures. The lateral heterostructures of two CDWs are entangled as topological excitations, which give rise to a CDW phase shift and the incommensuration without a conventional domain wall. A partially melted network of topological excitations and their vertices explain an unusual landscape of domains. The unconventional topological role of competing phases disclosed here can be widely applied to various incommensuration or phase coexistence phenomena in materials.
Collapse
Affiliation(s)
- Gyeongcheol Gye
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea, and Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Eunseok Oh
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea, and Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Han Woong Yeom
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea, and Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| |
Collapse
|
17
|
Gati E, Fischer JKH, Lunkenheimer P, Zielke D, Köhler S, Kolb F, von Nidda HAK, Winter SM, Schubert H, Schlueter JA, Jeschke HO, Valentí R, Lang M. Evidence for Electronically Driven Ferroelectricity in a Strongly Correlated Dimerized BEDT-TTF Molecular Conductor. PHYSICAL REVIEW LETTERS 2018; 120:247601. [PMID: 29957011 DOI: 10.1103/physrevlett.120.247601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Indexed: 06/08/2023]
Abstract
By applying measurements of the dielectric constants and relative length changes to the dimerized molecular conductor κ-(BEDT-TTF)_{2}Hg(SCN)_{2}Cl, we provide evidence for order-disorder type electronic ferroelectricity that is driven by the charge order within the (BEDT-TTF)_{2} dimers and stabilized by a coupling to the anions. According to our density functional theory calculations, this material is characterized by a moderate strength of dimerization. This system thus bridges the gap between strongly dimerized materials, often approximated as dimer-Mott systems at 1/2 filling, and nondimerized or weakly dimerized systems at 1/4 filling, exhibiting a charge order. Our results indicate that intradimer charge degrees of freedom are of particular importance in correlated κ-(BEDT-TTF)_{2}X salts and can create novel states, such as electronically driven multiferroicity or charge-order-induced quasi-one-dimensional spin liquids.
Collapse
Affiliation(s)
- Elena Gati
- Institute of Physics, Goethe-Universität, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| | - Jonas K H Fischer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
| | - Peter Lunkenheimer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
| | - David Zielke
- Institute of Physics, Goethe-Universität, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| | - Sebastian Köhler
- Institute of Physics, Goethe-Universität, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| | - Felizitas Kolb
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
| | - Hans-Albrecht Krug von Nidda
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
| | - Stephen M Winter
- Institute for Theoretical Physics, Goethe-Universität, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| | - Harald Schubert
- Institute of Physics, Goethe-Universität, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| | - John A Schlueter
- Division of Materials Research, National Science Foundation, Arlington, Virginia 22230, USA
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Harald O Jeschke
- Institute for Theoretical Physics, Goethe-Universität, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
- Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| | - Roser Valentí
- Institute for Theoretical Physics, Goethe-Universität, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| | - Michael Lang
- Institute of Physics, Goethe-Universität, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| |
Collapse
|
18
|
Bending and breaking of stripes in a charge ordered manganite. Nat Commun 2017; 8:1883. [PMID: 29192204 PMCID: PMC5709367 DOI: 10.1038/s41467-017-02156-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 11/10/2017] [Indexed: 11/08/2022] Open
Abstract
In charge-ordered phases, broken translational symmetry emerges from couplings between charge, spin, lattice, or orbital degrees of freedom, giving rise to remarkable phenomena such as colossal magnetoresistance and metal-insulator transitions. The role of the lattice in charge-ordered states remains particularly enigmatic, soliciting characterization of the microscopic lattice behavior. Here we directly map picometer scale periodic lattice displacements at individual atomic columns in the room temperature charge-ordered manganite Bi0.35Sr0.18Ca0.47MnO3 using aberration-corrected scanning transmission electron microscopy. We measure transverse, displacive lattice modulations of the cations, distinct from existing manganite charge-order models. We reveal locally unidirectional striped domains as small as ~5 nm, despite apparent bidirectionality over larger length scales. Further, we observe a direct link between disorder in one lattice modulation, in the form of dislocations and shear deformations, and nascent order in the perpendicular modulation. By examining the defects and symmetries of periodic lattice displacements near the charge ordering phase transition, we directly visualize the local competition underpinning spatial heterogeneity in a complex oxide.
Collapse
|
19
|
Liu M, Sternbach AJ, Basov DN. Nanoscale electrodynamics of strongly correlated quantum materials. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:014501. [PMID: 27811387 DOI: 10.1088/0034-4885/80/1/014501] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Electronic, magnetic, and structural phase inhomogeneities are ubiquitous in strongly correlated quantum materials. The characteristic length scales of the phase inhomogeneities can range from atomic to mesoscopic, depending on their microscopic origins as well as various sample dependent factors. Therefore, progress with the understanding of correlated phenomena critically depends on the experimental techniques suitable to provide appropriate spatial resolution. This requirement is difficult to meet for some of the most informative methods in condensed matter physics, including infrared and optical spectroscopy. Yet, recent developments in near-field optics and imaging enabled a detailed characterization of the electromagnetic response with a spatial resolution down to 10 nm. Thus it is now feasible to exploit at the nanoscale well-established capabilities of optical methods for characterization of electronic processes and lattice dynamics in diverse classes of correlated quantum systems. This review offers a concise description of the state-of-the-art near-field techniques applied to prototypical correlated quantum materials. We also discuss complementary microscopic and spectroscopic methods which reveal important mesoscopic dynamics of quantum materials at different energy scales.
Collapse
Affiliation(s)
- Mengkun Liu
- Department of Physics, Stony Brook University, Stony Brook, NY 11794, USA
| | | | | |
Collapse
|
20
|
Abstract
In complex oxides systems such as manganites, electronic phase separation (EPS), a consequence of strong electronic correlations, dictates the exotic electrical and magnetic properties of these materials. A fundamental yet unresolved issue is how EPS responds to spatial confinement; will EPS just scale with size of an object, or will the one of the phases be pinned? Understanding this behavior is critical for future oxides electronics and spintronics because scaling down of the system is unavoidable for these applications. In this work, we use La0.325Pr0.3Ca0.375MnO3 (LPCMO) single crystalline disks to study the effect of spatial confinement on EPS. The EPS state featuring coexistence of ferromagnetic metallic and charge order insulating phases appears to be the low-temperature ground state in bulk, thin films, and large disks, a previously unidentified ground state (i.e., a single ferromagnetic phase state emerges in smaller disks). The critical size is between 500 nm and 800 nm, which is similar to the characteristic length scale of EPS in the LPCMO system. The ability to create a pure ferromagnetic phase in manganite nanodisks is highly desirable for spintronic applications.
Collapse
|
21
|
Kim HS, Kim S, Kim K, Min BI, Cho YH, Wang L, Cheong SW, Yeom HW. Nanoscale Superconducting Honeycomb Charge Order in IrTe2. NANO LETTERS 2016; 16:4260-4265. [PMID: 27221583 DOI: 10.1021/acs.nanolett.6b01293] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Entanglement of charge orderings and other electronic orders such as superconductivity is in the core of challenging physics issues of complex materials including high temperature superconductivity. Here, we report on the observation of a unique nanometer scale honeycomb charge ordering of the cleaved IrTe2 surface, which hosts a superconducting state. IrTe2 was recently established to exhibit an intriguing cascade of stripe charge orders. The stripe phases coexist with a hexagonal phase, which is formed locally and falls into a superconducting state below 3 K. The atomic and electronic structures of the honeycomb and hexagon pattern of this phase are consistent with the charge order nature, but the superconductivity does not survive on neighboring stripe charge order domains. The present work provides an intriguing physics issue and a new direction of functionalization for two-dimensional materials.
Collapse
Affiliation(s)
- Hyo Sung Kim
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS) , Pohang 790-784, Korea
- Department of Physics, Pohang University of Science and Technology , Pohang 790-784, Korea
| | - Sooran Kim
- Department of Physics, Pohang University of Science and Technology , Pohang 790-784, Korea
| | - Kyoo Kim
- Department of Physics, Pohang University of Science and Technology , Pohang 790-784, Korea
| | - Byung Il Min
- Department of Physics, Pohang University of Science and Technology , Pohang 790-784, Korea
| | - Yong-Heum Cho
- Department of Physics, Pohang University of Science and Technology , Pohang 790-784, Korea
- Laboratory for Pohang Emergent Materials, Pohang University of Science and Technology , Pohang 790-784, Korea
| | - Lihai Wang
- Department of Physics, Pohang University of Science and Technology , Pohang 790-784, Korea
- Laboratory for Pohang Emergent Materials, Pohang University of Science and Technology , Pohang 790-784, Korea
| | - Sang-Wook Cheong
- Department of Physics, Pohang University of Science and Technology , Pohang 790-784, Korea
- Laboratory for Pohang Emergent Materials, Pohang University of Science and Technology , Pohang 790-784, Korea
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, New Jersey 08854, United States
| | - Han Woong Yeom
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS) , Pohang 790-784, Korea
- Department of Physics, Pohang University of Science and Technology , Pohang 790-784, Korea
| |
Collapse
|
22
|
Hattori AN, Fujiwara Y, Fujiwara K, Nguyen TVA, Nakamura T, Ichimiya M, Ashida M, Tanaka H. Identification of Giant Mott Phase Transition of Single Electric Nanodomain in Manganite Nanowall Wire. NANO LETTERS 2015; 15:4322-8. [PMID: 26007707 DOI: 10.1021/acs.nanolett.5b00264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In the scaling down of electronic devices, functional oxides with strongly correlated electron system provide advantages to conventional semiconductors, namely, huge switching owing to their phase transition and high carrier density, which guarantee their rich functionalities even at the 10 nm scale. However, understanding how their functionalities behave at a scale of 10 nm order is still a challenging issue. Here, we report the construction of the well-defined (La,Pr,Ca)MnO3 epitaxial oxide nanowall wire by combination of nanolithography and subsequent thin-film growth, which allows the direct investigation of its insulator-metal transition (IMT) at the single domain scale. We show that the width of a (La,Pr,Ca)MnO3 nanowall sample can be reduced to 50 nm, which is smaller than the observed 70-200 nm-size electronic domains, and that a single electronic nanodomain in (La,Pr,Ca)MnO3 exhibited an intrinsic first-order IMT with an unusually steep single-step change in its magnetoresistance and temperature-induced resistance due to the domains arrangement in series. A simple model of the first-order transition for single electric domains satisfactorily illustrates the IMT behavior from macroscale down to the nanoscale.
Collapse
Affiliation(s)
- Azusa N Hattori
- †Nanoscience and Nanotechnology Center, The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihoga-oka, Ibaraki, Osaka 567-0047, Japan
| | - Yasushi Fujiwara
- †Nanoscience and Nanotechnology Center, The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihoga-oka, Ibaraki, Osaka 567-0047, Japan
| | - Kohei Fujiwara
- †Nanoscience and Nanotechnology Center, The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihoga-oka, Ibaraki, Osaka 567-0047, Japan
| | - Thi Van Anh Nguyen
- †Nanoscience and Nanotechnology Center, The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihoga-oka, Ibaraki, Osaka 567-0047, Japan
| | - Takuro Nakamura
- †Nanoscience and Nanotechnology Center, The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihoga-oka, Ibaraki, Osaka 567-0047, Japan
| | - Masayoshi Ichimiya
- ‡Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
- §School of Engineering, The University of Shiga Prefecture, 2500 Hassaka-cho, Hikone, Shiga 522-8533, Japan
| | - Masaaki Ashida
- ‡Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - Hidekazu Tanaka
- †Nanoscience and Nanotechnology Center, The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihoga-oka, Ibaraki, Osaka 567-0047, Japan
| |
Collapse
|
23
|
Charge-ordering cascade with spin–orbit Mott dimer states in metallic iridium ditelluride. Nat Commun 2015; 6:7342. [DOI: 10.1038/ncomms8342] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 04/28/2015] [Indexed: 11/08/2022] Open
|
24
|
Pagliari L, Dapiaggi M, Maglia F, Sarkar T, Raychaudhuri AK, Chatterji T, Carpenter MA. Strain heterogeneity and magnetoelastic behaviour of nanocrystalline half-doped La, Ca manganite, La0.5Ca0.5MnO3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:435303. [PMID: 25299746 DOI: 10.1088/0953-8984/26/43/435303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Elastic and anelastic properties of La0.5Ca0.5MnO3 determined by resonant ultrasound spectroscopy in the frequency range ∼100-1200 kHz have been used to evaluate the role of grain size in determining the competition between ferromagnetism and Jahn-Teller/charge order of manganites which show colossal magneto resistance. At crystallite sizes of ∼75 and ∼135 nm the dominant feature is softening of the shear modulus as the charge order transition point, Tco (∼225 K), is approached from above and below, matching the form of softening seen previously in samples with 'bulk' properties. This is consistent with a bilinear dominant strain/order parameter coupling, which occurs between the tetragonal shear strain and the Jahn-Teller (Γ3(+)) order parameter. At crystallite sizes of ∼34 and ∼42 nm the charge ordered phase is suppressed but there is still softening of the shear modulus, with a minimum near Tco. This indicates that some degree of pseudoproper ferroelastic behaviour is retained. The primary cause of the suppresion of the charge ordered structure in nanocrystalline samples is therefore considered to be due to suppression of macroscopic strain, even though MnO6 octahedra must develop some Jahn-Teller distortions on a local length scale. This mechanism for stabilizing ferromagnetism differs from imposition of either an external magnetic field or a homogeneous external strain field (from a substrate), and is likely to lead both to local strain heterogeneity within the nanocrystallites and to different tilting of octahedra within the orthorhombic structure. An additional first order transition occurs near 40 K in all samples and appears to involve some very small strain contrast between two ferromagnetic structures.
Collapse
Affiliation(s)
- L Pagliari
- Dipartimento di Scienze della Terra, Università degli Studi di Milano, via Botticelli 23, 20133 Milan,Italy
| | | | | | | | | | | | | |
Collapse
|
25
|
Liang L, Li L, Wu H, Zhu X. Research progress on electronic phase separation in low-dimensional perovskite manganite nanostructures. NANOSCALE RESEARCH LETTERS 2014; 9:325. [PMID: 25024686 PMCID: PMC4080779 DOI: 10.1186/1556-276x-9-325] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 06/23/2014] [Indexed: 06/01/2023]
Abstract
Perovskite oxide manganites with a general formula of R1-x AxMnO3 (where R is a trivalent rare-earth element such as La, Pr, Sm, and A is a divalent alkaline-earth element such as Ca, Sr, and Ba) have received much attention due to their unusual electron-transport and magnetic properties, which are indispensable for applications in microelectronic, magnetic, and spintronic devices. Recent advances in the science and technology have resulted in the feature sizes of microelectronic devices based on perovskite manganite oxides down-scaling into nanoscale dimensions. At the nanoscale, low-dimensional perovskite manganite oxide nanostructures display novel physical properties that are different from their bulk and film counterparts. Recently, there is strong experimental evidence to indicate that the low-dimensional perovskite manganite oxide nanostructures are electronically inhomogeneous, consisting of different spatial regions with different electronic orders, a phenomenon that is named as electronic phase separation (EPS). As the geometry sizes of the low-dimensional manganite nanostructures are reduced to the characteristic EPS length scale (typically several tens of nanometers in manganites), the EPS is expected to be strongly modulated, leading to quite dramatic changes in functionality and more emergent phenomena. Therefore, reduced dimensionality opens a door to the new functionalities in perovskite manganite oxides and offers a way to gain new insight into the nature of EPS. During the past few years, much progress has been made in understanding the physical nature of the EPS in low-dimensional perovskite manganite nanostructures both from experimentalists and theorists, which have a profound impact on the oxide nanoelectronics. This nanoreview covers the research progresses of the EPS in low-dimensional perovskite manganite nanostructures such as nanoparticles, nanowires/nanotubes, and nanostructured films and/or patterns. The possible physical origins of the EPS are also discussed from the signatures of electronic inhomogeneities as well as some theoretical scenarios, to shed light on understanding this phenomenon. Finally, the perspectives to the future researches in this area are also outlined.
Collapse
Affiliation(s)
- Lizhi Liang
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China
| | - Lei Li
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China
| | - Heng Wu
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China
| | - Xinhua Zhu
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China
| |
Collapse
|
26
|
|
27
|
García J, Herrero-Martín J, Subías G, Blasco J, Andreu JS, Concepción Sánchez M. Incommensurate sinusoidal oxygen modulations in layered manganites La(1-x)Sr(1+x)MnO4 (x≥0.5). PHYSICAL REVIEW LETTERS 2012; 109:107202. [PMID: 23005321 DOI: 10.1103/physrevlett.109.107202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Indexed: 06/01/2023]
Abstract
We have studied the incommensurate-ordered phase in overdoped La0.4Sr1.6MnO4 by resonant x-ray diffraction at the Mn K edge. Weak resonant superlattice (h±0.2 h±0.2 0) and (h±0.4 h±0.4 0) reflections of the tetragonal structure were found below ~240 K. The energy, azimuth angle, and polarization dependencies of the resonant scattering have revealed sinusoidal modulations of the oxygen motions that are transverse and longitudinal to the tetragonal [110] direction. This result discards (Mn(3+),Mn(4+))-like stripe-type order but point to a charge-density-modulation picture.
Collapse
Affiliation(s)
- Joaquín García
- Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, Zaragoza, Spain.
| | | | | | | | | | | |
Collapse
|
28
|
Ulbrich H, Steffens P, Lamago D, Sidis Y, Braden M. Hourglass dispersion in overdoped single-layered manganites. PHYSICAL REVIEW LETTERS 2012; 108:247209. [PMID: 23004321 DOI: 10.1103/physrevlett.108.247209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Indexed: 06/01/2023]
Abstract
The incommensurate stripelike magnetic ordering in two single-layered manganites, Nd0.33Sr1.67MnO4 and Pr0.33Ca1.67MnO4, is found to exhibit an hourglasslike excitation spectrum very similar to that seen in various cuprates superconductors, but only for sufficiently short correlation lengths. Several characteristic features of an hourglass dispersion can be identified: enhancement of intensity at the merging of the incommensurate branches, rotation of the intensity maxima with higher energy transfer, and suppression of the outward-dispersing branches at low energy. The correlation length of the magnetic ordering and the large ratio of intra- to interstripe couplings are identified as the decisive parameters causing the hourglass shape of the spectrum.
Collapse
Affiliation(s)
- H Ulbrich
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany.
| | | | | | | | | |
Collapse
|
29
|
Ni H, Yue Z, Zhao K, Xiang W, Zhao S, Wang A, Kong YC, Wong HK. Magnetical and electrical tuning of transient photovoltaic effects in manganite-based heterojunctions. OPTICS EXPRESS 2012; 20:A406-A411. [PMID: 22712088 DOI: 10.1364/oe.20.00a406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Magnetically and bias current tunable transient photovoltaic (TPV) responses have been investigated in a manganite-based heterojunction composed of a La2/3Ca1/3MnO3 film and an n-type Si substrate at ambient temperature. Under irradiation of 248 nm pulsed laser with 20 ns duration the TPV peak values can be modulated in a range of -125 to 138 mV when the applied magnetic field perpendicular to the interface changes from -6.4 to + 6.4 kOe, and the relative variations (TPV(H) - TPV(0))/TPV(0) reach up to about 1000%. In addition, TPV responses can be also affected by bias current, and the photoresponse peaks change from positive to negative with the currents from -350 to 350 μA. These results indicate that the manganite-based heterojunction can be used for magnetically and electrically tunable ultraviolet photodetectors.
Collapse
Affiliation(s)
- Hao Ni
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Li X, Song S, Wang X, Liu D, Zhang H. Self-assembled 3D flower-like hierarchical Fe3O4/KxMnO2 core–shell architectures and their application for removal of dye pollutants. CrystEngComm 2012. [DOI: 10.1039/c2ce06349b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
31
|
Zheng L, Su W, Qi Z, Xu Y, Zhou M, Xie Y. First-order metal-insulator transition and infrared identification of shape-controlled magnetite nanocrystals. NANOTECHNOLOGY 2011; 22:485706. [PMID: 22071878 DOI: 10.1088/0957-4484/22/48/485706] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The first-order metal-insulator transition (MIT) in magnetite has been known for a long time but is still controversial in its nature. In this study, well-defined magnetite nanocrystals (NCs) with controllable size, shape and terminated surface are first employed to elucidate this important issue, and new discoveries such as a highly suppressed phase transition temperature are identified by monitoring the variable-temperature electric resistance and infrared spectroscopy. Significantly, by carefully comparing the infrared vibrational bands of the as-prepared magnetite NCs with octahedral and cubic shapes, respectively, we found that these two forms of magnetite NCs exhibited different transmittance changes and frequency shifts of the infrared characteristics, presumably due to the differences in the lattice distortions on the corresponding {001} and {111} terminal surfaces. This result produced evidence in support of the charge ordering of Fe atoms along the low dimensionality at octahedral B sites undergoing the MIT. Taken together, infrared identification was proposed to be an available characterization strategy for MIT, which can reflect more information on the elusive lattice distortion of crystallographic structure or exposed surfaces.
Collapse
Affiliation(s)
- Lei Zheng
- Department of Nanomaterials and Nanochemistry, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | | | | | | | | | | |
Collapse
|
32
|
Localization of electrons due to orbitally ordered bi-stripes in the bilayer manganite La(2-2x)Sr(1+2x)Mn2O7 (x ~ 0.59). Proc Natl Acad Sci U S A 2011; 108:11799-803. [PMID: 21715662 DOI: 10.1073/pnas.1018604108] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Electronic phases with stripe patterns have been intensively investigated for their vital roles in unique properties of correlated electronic materials. How these real-space patterns affect the conductivity and other properties of materials (which are usually described in momentum space) is one of the major challenges of modern condensed matter physics. By studying the electronic structure of La(2-2x)Sr(1+2x)Mn(2)O(7) (x ∼ 0.59) and in combination with earlier scattering measurements, we demonstrate the variation of electronic properties accompanying the melting of so-called bi-stripes in this material. The static bi-stripes can strongly localize the electrons in the insulating phase above T(c) ∼ 160 K, while the fraction of mobile electrons grows, coexisting with a significant portion of localized electrons when the static bi-stripes melt below T(c). The presence of localized electrons below T(c) suggests that the melting bi-stripes exist as a disordered or fluctuating counterpart. From static to melting, the bi-stripes act as an atomic-scale electronic valve, leading to a "colossal" metal-insulator transition in this material.
Collapse
|
33
|
Ulbrich H, Senff D, Steffens P, Schumann OJ, Sidis Y, Reutler P, Revcolevschi A, Braden M. Evidence for charge orbital and spin stripe order in an overdoped manganite. PHYSICAL REVIEW LETTERS 2011; 106:157201. [PMID: 21568606 DOI: 10.1103/physrevlett.106.157201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Indexed: 05/30/2023]
Abstract
Overdoped La0.42Sr1.58MnO4 exhibits a complex ordering of charges, orbitals, and spins. Neutron diffraction experiments reveal three incommensurate and one commensurate order parameters to be tightly coupled. The position and the shape of the distinct superstructure scattering as well as higher-order signals are inconsistent with a harmonic charge and spin-density-wave picture but point to a stripe arrangement in which ferromagnetic zigzag chains are disrupted by excess Mn(4+).
Collapse
Affiliation(s)
- H Ulbrich
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln, Germany
| | | | | | | | | | | | | | | |
Collapse
|
34
|
Chen H, Chu PK, He J, Hu T, Yang M. Porous magnetic manganese oxide nanostructures: synthesis and their application in water treatment. J Colloid Interface Sci 2011; 359:68-74. [PMID: 21507410 DOI: 10.1016/j.jcis.2011.03.089] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2011] [Revised: 03/22/2011] [Accepted: 03/25/2011] [Indexed: 11/29/2022]
Abstract
Magnetic manganese oxide nanostructures are fabricated at room temperature by mixing a KMnO(4) solution and oleic acid capped Fe(3)O(4) particles. Oleic acid molecules capped Fe(3)O(4) particles are oxidized by potassium permanganate (KMnO(4)) in an aqueous solution to produce porous magnetic manganese oxide nanostructures. The synthesis technique can be extended to other MnO(x) structures with composition of different nanocrystals, such as quantum dots, noble metal crystals which may have important applications as catalysts, adsorbents, electrodes and advanced materials in many scientific disciplines. Transmission electron microscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, and nitrogen adsorption-desorption measurements are employed to characterize the structures. As an adsorbent in water treatment, the nanostructures possess a large adsorption capability and high organic pollutant removal rates due to the large surface area and pore volume. The nanostructures are recyclable as their adsorption capability can be recovered by combustion. Furthermore, the strong magnetism exhibited by the structures provides an easy and efficient separation means in wastewater treatment under an external magnetic field.
Collapse
Affiliation(s)
- Hongmin Chen
- Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
| | | | | | | | | |
Collapse
|
35
|
Fisher B, Genossar J, Patlagan L, Kar-Narayan S, Moya X, Sánchez D, Midgley PA, Mathur ND. The absence of charge-density-wave sliding in epitaxial charge-ordered Pr(0.48)Ca(0.52)MnO(3) films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:275602. [PMID: 21399261 DOI: 10.1088/0953-8984/22/27/275602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
For an epitaxial Pr(0.48)Ca(0.52)MnO(3) film on NdGaO(3), we use transmission electron microscopy to observe a 'charge-ordered' superlattice along the in-plane direction a. The same film shows no electrical signatures of charge order. The in-plane electrical anisotropy ρ(a)/ρ(c) = 28 is constant, and there is no evidence of sliding charge density waves up to the large field of ∼10(3) V cm(-1).
Collapse
Affiliation(s)
- B Fisher
- Department of Physics, Technion, Haifa 32000, Israel.
| | | | | | | | | | | | | | | |
Collapse
|
36
|
Miyazaki J, Matsudaira K, Shimizu Y, Itoh M, Nagamine Y, Mori S, Kim JE, Kato K, Takata M, Katsufuji T. Formation of a three-dimensional network of V trimers in A2V13O22 (A=Ba, Sr). PHYSICAL REVIEW LETTERS 2010; 104:207201. [PMID: 20867054 DOI: 10.1103/physrevlett.104.207201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Indexed: 05/29/2023]
Abstract
We found that in A2V13O22 (A=Ba, Sr), which contains a trilayer slab of VO in the sodium-chloride structure with periodically missing ions, the trimerization of V ions occurs at 290 K (A=Ba) and 380 K (A=Sr). V trimers form a three-dimensional network, but some V ions remain untrimerized in these compounds. The suppression of magnetic susceptibility with trimerization and the existence of a Curie tail at low temperatures, together with the result of NMR measurement, indicate that the V trimers are spin singlet, whereas the untrimerized V ions have a magnetic moment; i.e., there is a spontaneous separation between nonmagnetic and magnetic ions in the crystal.
Collapse
Affiliation(s)
- J Miyazaki
- Department of Physics, Waseda University, Tokyo 169-8555, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Koumoulis D, Panopoulos N, Reyes A, Fardis M, Pissas M, Douvalis A, Bakas T, Argyriou DN, Papavassiliou G. Direct NMR evidence of phase solitons in the spin ground state of overdoped manganites. PHYSICAL REVIEW LETTERS 2010; 104:077204. [PMID: 20366913 DOI: 10.1103/physrevlett.104.077204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Indexed: 05/29/2023]
Abstract
Charge ordering phenomena in overdoped La1-xCaxMnO3 (LCMO) manganites with x>or=0.5 are generally believed to be associated with the formation of charge stripes composed of alternating Mn3+ and Mn4+ charges. However, a number of recent experiments indicate that instead of stripes the charge in these systems is spatially organized in a uniform charge density wave. At the same time theory predicts that the ground state is modulated by an incommensurate (IC) orbital and charge soliton lattice. Here, by using nuclear magnetic resonance we provide the first direct evidence that the spin ground state in overdoped LCMO manganites is IC modulated with phase solitons. At higher temperatures the solitonic superstructure is replaced by a uniform spin-density wave, subjected to coherent slow fluctuations, showing a striking similarity with slow fluctuations in the striped phase of high T{c} cuprates and nickelates.
Collapse
Affiliation(s)
- D Koumoulis
- Institute of Materials Science, NCSR, Demokritos, 153 10 Aghia Paraskevi, Athens, Greece
| | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Dai Y, Lu X, McKiernan M, Lee EP, Sun Y, Xia Y. Hierarchical nanostructures of K-birnessite nanoplates on anatase nanofibers and their application for decoloration of dye solution. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c000446d] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
39
|
Rout GC, Panda S. Microscopic theory of longitudinal sound velocity in charge ordered manganites. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:416001. [PMID: 21693999 DOI: 10.1088/0953-8984/21/41/416001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A microscopic theory of longitudinal sound velocity in a manganite system is reported here. The manganite system is described by a model Hamiltonian consisting of charge density wave (CDW) interaction in the e(g) band, an exchange interaction between spins of the itinerant e(g) band electrons and the core t(2g) electrons, and the Heisenberg interaction of the core level spins. The magnetization and the CDW order parameters are considered within mean-field approximations. The phonon Green's function was calculated by Zubarev's technique and hence the longitudinal velocity of sound was finally calculated for the manganite system. The results show that the elastic spring involved in the velocity of sound exhibits strong stiffening in the CDW phase with a decrease in temperature as observed in experiments.
Collapse
Affiliation(s)
- G C Rout
- Condensed Matter Physics Group, PG Department of Applied Physics and Ballistics, FM University, Balasore 756 019, India
| | | |
Collapse
|
40
|
Ma C, Yang HX, Zeng LJ, Li ZA, Zhang Y, Qin YB, Li JQ. Effects of layered structural features on charge/orbital ordering in (La, Sr)(n+1)Mn(n)O(3n+1) (n = 1 and 2). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:045601. [PMID: 21715815 DOI: 10.1088/0953-8984/21/4/045601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The charge/orbital ordering (COO) of the layered mixed-valence manganites (La,Sr)(n+1)Mn(n)O(3n+1) (n = 1 and 2) is examined by first-principles calculations and discussed in comparison with the La(0.5)Ca(0.5)MnO(3) perovskite phase ([Formula: see text]). The results demonstrated that the layered structural features could yield not only visibly weak coupling between Mn-O layers but also various features in the orbital ordering associated with different types of local structural distortions. In both La(0.5)Sr(1.5)MnO(4) (n = 1) and LaSr(2)Mn(2)O(7) (n = 2) phases, the orbital ordering can be chiefly assigned to the d(x(2)-y(2)) orbital, in contrast with the zigzag-type d(z(2)) orbital ordering in the [Formula: see text] perovskite phase. Our theoretical analysis shows that a variety of essential factors, including the local structural distortions of the MnO(6) octahedra, the on-site Coulomb interaction, and magnetic interaction, have to be properly considered in order to achieve acceptable COO ground states for the layered variants in (La,Sr)(n+1)Mn(n)O(3n+1).
Collapse
Affiliation(s)
- C Ma
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, People's Republic of China
| | | | | | | | | | | | | |
Collapse
|
41
|
Jang YH, Gervais F, Lansac Y. A-site ordering in colossal magnetoresistance manganite La[sub 1−x]Sr[sub x]MnO[sub 3]? Molecular dynamics simulations and quantum mechanics calculations. J Chem Phys 2009; 131:094503. [DOI: 10.1063/1.3190533] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
42
|
Nucara A, Maselli P, Calvani P, Sopracase R, Ortolani M, Gruener G, Guidi MC, Schade U, García J. Observation of charge-density-wave excitations in manganites. PHYSICAL REVIEW LETTERS 2008; 101:066407. [PMID: 18764484 DOI: 10.1103/physrevlett.101.066407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Indexed: 05/26/2023]
Abstract
In the optical conductivity of four different manganites with commensurate charge order (CO), strong peaks appear in the meV range below the ordering temperature T_{CO}. They are similar to those reported for one-dimensional charge density waves (CDW) and are assigned to pinned phasons. The peaks and their overtones allow one to obtain, for La_{1-n/8}Ca_{n/8}MnO_{3} with n=5, 6, the electron-phonon coupling, the effective mass of the CO system, and its contribution to the dielectric constant. These results support a description of the CO in La-Ca manganites in terms of moderately weak coupling and of the CDW theory.
Collapse
Affiliation(s)
- A Nucara
- CNR-INFM Coherentia and Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale A. Moro 2, I-00185 Roma, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Siwach PK, Singh HK, Srivastava ON. Low field magnetotransport in manganites. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2008; 20:273201. [PMID: 21694362 DOI: 10.1088/0953-8984/20/27/273201] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The perovskite manganites with generic formula RE(1-x)AE(x)MnO(3) (RE = rare earth, AE = Ca, Sr, Ba and Pb) have drawn considerable attention, especially following the discovery of colossal magnetoresistance (CMR). The most fundamental property of these materials is strong correlation between structure, transport and magnetic properties. They exhibit extraordinary large magnetoresistance named CMR in the vicinity of the insulator-metal/paramagnetic-ferromagnetic transition at relatively large applied magnetic fields. However, for applied aspects, occurrence of significant CMR at low applied magnetic fields would be required. This review consists of two sections: in the first section we have extensively reviewed the salient features, e.g. structure, phase diagram, double-exchange mechanism, Jahn-Teller effect, different types of ordering and phase separation of CMR manganites. The second is devoted to an overview of experimental results on CMR and related magnetotransport characteristics at low magnetic fields for various doped manganites having natural grain boundaries such as polycrystalline, nanocrystalline bulk and films, manganite-based composites and intrinsically layered manganites, and artificial grain boundaries such as bicrystal, step-edge and laser-patterned junctions. Some other potential magnetoresistive materials, e.g. pyrochlores, chalcogenides, ruthenates, diluted magnetic semiconductors, magnetic tunnel junctions, nanocontacts etc, are also briefly dealt with. The review concludes with an overview of grain-boundary-induced low field magnetotransport behavior and prospects for possible applications.
Collapse
Affiliation(s)
- P K Siwach
- Physics Department, Banaras Hindu University, Varanasi-221 005, India
| | | | | |
Collapse
|
44
|
Shenoy VB, Rao CNR. Electronic phase separation and other novel phenomena and properties exhibited by mixed-valent rare-earth manganites and related materials. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2008; 366:63-82. [PMID: 17827125 DOI: 10.1098/rsta.2007.2140] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Transition metal oxides, such as the mixed-valent rare-earth manganites Ln(1-x)AxMnO3 (Ln, rare-earth ion, and A, alkaline-earth ion), show a variety of electronic orders with spatially correlated charge, spin and orbital arrangements, which in turn give rise to many fascinating phenomena and properties. These materials are also electronically inhomogeneous, i.e. they contain disjoint spatial regions with different electronic orders. Not only do we observe signatures of such electronic phase separation in a variety of properties, but we can also observe the different 'phases' visually through different types of imaging. We discuss various experiments pertaining to electronic orders and electronic inhomogeneities in the manganites and present a discussion of theoretical approaches to their understanding. It is noteworthy that the mixed-valent rare-earth cobaltates of the type Ln(1-x)AxCoO3 also exhibit electronic inhomogeneities just as the manganites.
Collapse
Affiliation(s)
- Vijay B Shenoy
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560 012, India
| | | |
Collapse
|
45
|
Cox S, Singleton J, McDonald RD, Migliori A, Littlewood PB. Sliding charge-density wave in manganites. NATURE MATERIALS 2008; 7:25-30. [PMID: 18059276 DOI: 10.1038/nmat2071] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2007] [Accepted: 10/26/2007] [Indexed: 05/25/2023]
Abstract
Stripe and chequerboard phases appear in many metal oxide compounds, and are thought to be linked to exotic behaviour such as high-temperature superconductivity and colossal magnetoresistance. It is therefore extremely important to understand the fundamental nature of such phases. The so-called stripe phase of the manganites has long been interpreted as the localization of charge at atomic sites. Here, we present resistance measurements on La(0.50)Ca(0.50)MnO(3) that strongly suggest that this state is in fact a prototypical charge-density wave (CDW) that undergoes collective transport. Dramatic resistance hysteresis effects and broadband noise properties are observed, both of which are typical of sliding CDW systems. Moreover, the high levels of disorder typical of manganites result in behaviour similar to that of well-known disordered CDW materials. The CDW-type behaviour of the manganite superstructure suggests that unusual transport and structural properties do not require exotic physics, but could emerge when a well-understood phase (the CDW) coexists with disorder.
Collapse
Affiliation(s)
- Susan Cox
- National High Magnetic Field Laboratory, Ms-E536, Los Alamos National Laboratory, New Mexico 87545, USA.
| | | | | | | | | |
Collapse
|
46
|
Loudon JC, Kourkoutis LF, Ahn JS, Zhang CL, Cheong SW, Muller DA. Valence changes and structural distortions in "charge ordered" manganites quantified by atomic-scale scanning transmission electron microscopy. PHYSICAL REVIEW LETTERS 2007; 99:237205. [PMID: 18233407 DOI: 10.1103/physrevlett.99.237205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Indexed: 05/25/2023]
Abstract
We investigate the microscopic nature of the "charge ordering" modulation in mixed-valent manganites in real space using scanning transmission electron microscopy. The modulation in Bi0.5Sr0.4Ca0.1MnO3 has a uniform periodicity appearing as stripes in high angle annular dark field images. Geometric phase analysis shows the modulation to be a displacement wave with transverse amplitude (0.008+/-0.001)a and longitudinal amplitude (0.003+/-0.001)a. Series of energy loss spectra taken across the stripes show no periodic changes and place an upper bound of +/-0.04 on any valence changes of the Mn ions.
Collapse
Affiliation(s)
- J C Loudon
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | | | | | | | | | | |
Collapse
|
47
|
Yu C, Shi J, Yan D. A Simple Controlled Salt Decomposition Route to Synthesize Nanoporous Mn2O3Materials with Tunable Pore Structure and Narrow Pore Distribution. CHEM LETT 2007. [DOI: 10.1246/cl.2007.1502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
48
|
Liu XJ, Zhang S, Chai P, Meng J. Charge ordering induced metal–semiconductor transition in Ag2BiO3: A first-principles study. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.06.089] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
49
|
Ning L, Guoqing Y, Huanyin G. Research on Electron Spin Resonance of La0.3 Ca0.7 Mn1-x WxO3 (x = 0.04, 0.08, 0.12) System. J RARE EARTH 2007. [DOI: 10.1016/s1002-0721(07)60475-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
50
|
Yu XZ, Arima T, Kaneko Y, He JP, Mathieu R, Asaka T, Hara T, Kimoto K, Matsui Y, Tokura Y. Direct observation of the bandwidth-disorder induced variation of charge/orbital ordering structure in RE(0.5)(Ca(1-y)Sr(y))(1.5)MnO(4). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2007; 19:172203. [PMID: 21690937 DOI: 10.1088/0953-8984/19/17/172203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Changes in the charge/orbital ordering (CO/OO) structure with the bandwidth of the e(g) band and quenched disorder were investigated in doped manganites RE(0.5)(Ca(1-y)Sr(y))(1.5)MnO(4)(RE = Pr,Eu) with a single-layer perovskite structure. A systematic study of the modulation structure associated with the CO/OO phase demonstrated that the long-range commensurate structure changes to a short-range incommensurate structure with increasing Sr content through the enhancement of the bandwidth and quenched disorder in these systems. At the same time, the transition temperature of CO/OO (T(CO/OO)) decreases. Changes in structure and T(CO/OO) with different A-site combinations reveal that the CO/OO phase is strongly suppressed by the widening of the e(g) band and the stronger quenched disorder in these layered manganites.
Collapse
Affiliation(s)
- X Z Yu
- Spin Super Structure Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency, Tsukuba 305-8562, Japan. Advanced Electron Microscopy Group, National Institute for Materials Science, Tsukuba, 305-0044, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|