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Bai H, Liu D, Pan H. LaOMS 2 (M = Ti, V, and Cr): novel crystal spin valves without contact. MATERIALS HORIZONS 2023; 10:5126-5132. [PMID: 37695805 DOI: 10.1039/d3mh01182h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/13/2023]
Abstract
2D materials are widely investigated for application in nanodevices and spintronics. Here, we demonstrate that a family of structures, LaOMS2 (M = Ti, V, and Cr), where a La2O2 layer is sandwiched between two magnetic MS2 layers, are suitable to be used as spin valves without contact. We show that they are stable and exhibit unique magnetic and electronic properties. We find that (1) each MS2 layer is ferromagnetic with the magnetic moment mainly contributed by the M ion and the coupling between the two MS2 layers in one structure is negligible due to the blocking of the La2O2 layer; (2) LaOMS2 can be a half-metal in the ferromagnetic (FM) state and a conductor in the interlayer antiferromagnetic (inter-AFM) state, and the total energies of the two states are almost identical; (3) the magnetic properties and exchange energy can be effectively controlled by contacting with other materials; and (4) a 100% spin current is achieved in FM LaOMS2. Our results provide not only novel structures for practical application in spintronics, but also strategies for designing new devices.
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Affiliation(s)
- Haoyun Bai
- Institute of Applied Physics and Materials Engineering, University of Macau, Macao SAR, 999078, P. R. China.
| | - Di Liu
- Institute of Applied Physics and Materials Engineering, University of Macau, Macao SAR, 999078, P. R. China.
| | - Hui Pan
- Institute of Applied Physics and Materials Engineering, University of Macau, Macao SAR, 999078, P. R. China.
- Department of Physics and Chemistry, Faculty of Science and Technology, University of Macau, Macao SAR, 999078, P. R. China
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2
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Meng M, Sun Y, Li Y, An Q, Wang Z, Lin Z, Yang F, Zhu X, Gao P, Guo J. Three dimensional band-filling control of complex oxides triggered by interfacial electron transfer. Nat Commun 2021; 12:2447. [PMID: 33907193 PMCID: PMC8079372 DOI: 10.1038/s41467-021-22790-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 03/29/2021] [Indexed: 11/09/2022] Open
Abstract
The d-band-filling of transition metals in complex oxides plays an essential role in determining their structural, electronic and magnetic properties. Traditionally, at the oxide heterointerface, band-filling control has been achieved via electrostatic modification in the structure of field-effect transistors or electron transfer, which is limited to the quasi-two-dimension at the interface. Here we report a three-dimensional (3D) band-filling control by changing the local lattice coordination in a designed oxide heterostructure. At the LaCoO3/LaTiO3 heterointerface, due to the Fermi level mismatch, electrons transfer from LaTiO3 to LaCoO3. This triggers destabilisation of the CoO6 octahedrons, i.e. the formation of lattice configurations with a reduced Co valence. The associated oxygen migration results in the 3D topotactic phase transition of LaCoO3. Tuned by the thickness of LaTiO3, different crystalline phases and band-fillings of Co occur, leading to the emergence of different magnetic ground states.
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Affiliation(s)
- Meng Meng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Yuanwei Sun
- International Center for Quantum Materials, and Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
| | - Yuehui Li
- International Center for Quantum Materials, and Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
| | - Qichang An
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zhenzhen Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zijian Lin
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Fang Yang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Xuetao Zhu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China.,Songshan Lake Materials Laboratory, Dongguan, Guangdong, China
| | - Peng Gao
- International Center for Quantum Materials, and Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China. .,Collaborative Innovation Center of Quantum Matter, Beijing, China.
| | - Jiandong Guo
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, China. .,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China. .,Songshan Lake Materials Laboratory, Dongguan, Guangdong, China. .,Beijing Academy of Quantum Information Sciences, Beijing, China.
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3
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Chen B, Gauquelin N, Jannis D, Cunha DM, Halisdemir U, Piamonteze C, Lee JH, Belhadi J, Eltes F, Abel S, Jovanović Z, Spreitzer M, Fompeyrine J, Verbeeck J, Bibes M, Huijben M, Rijnders G, Koster G. Strain-Engineered Metal-to-Insulator Transition and Orbital Polarization in Nickelate Superlattices Integrated on Silicon. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2004995. [PMID: 33175414 DOI: 10.1002/adma.202004995] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 09/27/2020] [Indexed: 06/11/2023]
Abstract
Epitaxial growth of SrTiO3 (STO) on silicon greatly accelerates the monolithic integration of multifunctional oxides into the mainstream semiconductor electronics. However, oxide superlattices (SLs), the birthplace of many exciting discoveries, remain largely unexplored on silicon. In this work, LaNiO3 /LaFeO3 SLs are synthesized on STO-buffered silicon (Si/STO) and STO single-crystal substrates, and their electronic properties are compared using dc transport and X-ray absorption spectroscopy. Both sets of SLs show a similar thickness-driven metal-to-insulator transition, albeit with resistivity and transition temperature modified by the different amounts of strain. In particular, the large tensile strain promotes a pronounced Ni 3 d x 2 - y 2 orbital polarization for the SL grown on Si/STO, comparable to that reported for LaNiO3 SL epitaxially strained to DyScO3 substrate. Those results illustrate the ability to integrate oxide SLs on silicon with structure and property approaching their counterparts grown on STO single crystal, and also open up new prospects of strain engineering in functional oxides based on the Si platform.
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Affiliation(s)
- Binbin Chen
- MESA+ Institute for Nanotechnology, University of Twente, Enschede, 7500 AE, The Netherlands
| | - Nicolas Gauquelin
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Antwerp, 2020, Belgium
| | - Daen Jannis
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Antwerp, 2020, Belgium
| | - Daniel M Cunha
- MESA+ Institute for Nanotechnology, University of Twente, Enschede, 7500 AE, The Netherlands
| | - Ufuk Halisdemir
- MESA+ Institute for Nanotechnology, University of Twente, Enschede, 7500 AE, The Netherlands
| | - Cinthia Piamonteze
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Villigen, CH-5232, Switzerland
| | - Jin Hong Lee
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, Palaiseau, 91767, France
| | - Jamal Belhadi
- Advanced Materials Department, Jožef Stefan Institute, Ljubljana, 1000, Slovenia
| | - Felix Eltes
- IBM Research Europe, Rüschlikon, Zürich, 8803, Switzerland
- Lumiphase AG, Zürich, 8003, Switzerland
| | - Stefan Abel
- IBM Research Europe, Rüschlikon, Zürich, 8803, Switzerland
- Lumiphase AG, Zürich, 8003, Switzerland
| | - Zoran Jovanović
- Advanced Materials Department, Jožef Stefan Institute, Ljubljana, 1000, Slovenia
- Laboratory of Physics, Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, 11000, Serbia
| | - Matjaž Spreitzer
- Advanced Materials Department, Jožef Stefan Institute, Ljubljana, 1000, Slovenia
| | - Jean Fompeyrine
- IBM Research Europe, Rüschlikon, Zürich, 8803, Switzerland
- Lumiphase AG, Zürich, 8003, Switzerland
| | - Johan Verbeeck
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Antwerp, 2020, Belgium
| | - Manuel Bibes
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, Palaiseau, 91767, France
| | - Mark Huijben
- MESA+ Institute for Nanotechnology, University of Twente, Enschede, 7500 AE, The Netherlands
| | - Guus Rijnders
- MESA+ Institute for Nanotechnology, University of Twente, Enschede, 7500 AE, The Netherlands
| | - Gertjan Koster
- MESA+ Institute for Nanotechnology, University of Twente, Enschede, 7500 AE, The Netherlands
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4
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Wang L, Yang Z, Bowden ME, Freeland JW, Sushko PV, Spurgeon SR, Matthews B, Samarakoon WS, Zhou H, Feng Z, Engelhard MH, Du Y, Chambers SA. Hole-Trapping-Induced Stabilization of Ni 4 + in SrNiO 3 /LaFeO 3 Superlattices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2005003. [PMID: 33006412 DOI: 10.1002/adma.202005003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 09/06/2020] [Indexed: 06/11/2023]
Abstract
Creating new functionality in materials containing transition metals is predicated on the ability to control the associated charge states. For a given transition metal, there is an upper limit on valence that is not exceeded under normal conditions. Here, it is demonstrated that this limit of 3+ for Ni and Fe can be exceeded via synthesis of (SrNiO3 )m /(LaFeO3 )n superlattices by tuning n and m. The Goldschmidt tolerance constraints are lifted, and SrNi4+ O3 with holes on adjacent O anions is stabilized as a perovskite at the single-unit-cell level (m = 1). Holding m = 1, spectroscopy reveals that the n = 1 superlattice contains Ni3+ and Fe4+ , whereas Ni4+ and Fe3+ are observed in the n = 5 superlattice. It is revealed that the B-site cation valences can be tuned by controlling the magnitude of the FeO6 octahedral rotations, which, in turn, determine the energy balance between Ni3+ /Fe4+ and Ni4+ /Fe3+ , thus controlling emergent electrical properties such as the band alignment and resulting hole confinement. This approach can be extended to other systems for synthesizing novel, metastable layered structures with new functionalities.
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Affiliation(s)
- Le Wang
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Zhenzhong Yang
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Mark E Bowden
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - John W Freeland
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Peter V Sushko
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Steven R Spurgeon
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Bethany Matthews
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Widitha S Samarakoon
- School of Chemical, Biological and Environment Engineering, Oregon State University, Corvallis, OR, 97331, USA
| | - Hua Zhou
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Zhenxing Feng
- School of Chemical, Biological and Environment Engineering, Oregon State University, Corvallis, OR, 97331, USA
| | - Mark H Engelhard
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Yingge Du
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Scott A Chambers
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
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5
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Yin L, Mi W. Progress in BiFeO 3-based heterostructures: materials, properties and applications. NANOSCALE 2020; 12:477-523. [PMID: 31850428 DOI: 10.1039/c9nr08800h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
BiFeO3-based heterostructures have attracted much attention for potential applications due to their room-temperature multiferroic properties, proper band gaps and ultrahigh ferroelectric polarization of BiFeO3, such as data storage, optical utilization in visible light regions and synapse-like function. Here, this work aims to offer a systematic review on the progress of BiFeO3-based heterostructures. In the first part, the optical, electric, magnetic, and valley properties and their interactions in BiFeO3-based heterostructures are briefly reviewed. In the second part, the morphologies of BiFeO3 and medium materials in the heterostructures are discussed. Particularly, in the third part, the physical properties and underlying mechanism in BiFeO3-based heterostructures are discussed thoroughly, such as the photovoltaic effect, electric field control of magnetism, resistance switching, and two-dimensional electron gas and valley characteristics. The fourth part illustrates the applications of BiFeO3-based heterostructures based on the materials and physical properties discussed in the second and third parts. This review also includes a future prospect, which can provide guidance for exploring novel physical properties and designing multifunctional devices.
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Affiliation(s)
- Li Yin
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, School of Science, Tianjin University, Tianjin 300354, China.
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6
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Yu T, Deng B, Zhou L, Chen P, Liu Q, Wang C, Ning X, Zhou J, Bian Z, Luo Z, Qiu C, Shi XQ, He H. Polarity and Spin-Orbit Coupling Induced Strong Interfacial Exchange Coupling: An Asymmetric Charge Transfer in Iridate-Manganite Heterostructure. ACS APPLIED MATERIALS & INTERFACES 2019; 11:44837-44843. [PMID: 31680512 DOI: 10.1021/acsami.9b14641] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Charge transfer is of particular importance in manipulating the interface physics in transition-metal oxide heterostructures. In this work, we have fabricated epitaxial bilayers composed of polar 3d LaMnO3 and nonpolar 5d SrIrO3. Systematic magnetic measurements reveal an unexpectedly large exchange bias effect in the bilayer, together with a dramatic enhancement of the coercivity of LaMnO3. Based on first-principle calculations and X-ray absorption spectroscopy measurements, such a strong interfacial magnetic coupling is found closely associated with the polar nature of LaMnO3 and the strong spin-orbit interaction in SrIrO3, which collectively drive an asymmetric interfacial charge transfer and lead to the emergence of an interfacial reentrant spin/superspin glass state. Our study provides a new insight into the charge transfer in transition-metal oxide heterostructures and offers a novel means to tune the interfacial exchange coupling for a variety of device applications.
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Affiliation(s)
- Tao Yu
- Department of Physics , Southern University of Science and Technology , Shenzhen 518055 , China
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology , Wuhan University , Wuhan 430072 , China
| | - Bei Deng
- Department of Physics , Southern University of Science and Technology , Shenzhen 518055 , China
| | - Liang Zhou
- Department of Physics , Southern University of Science and Technology , Shenzhen 518055 , China
| | - Pingbo Chen
- Department of Physics , Southern University of Science and Technology , Shenzhen 518055 , China
| | - Qiying Liu
- Department of Physics , Southern University of Science and Technology , Shenzhen 518055 , China
| | - Cailin Wang
- Department of Physics , Southern University of Science and Technology , Shenzhen 518055 , China
| | - Xingkun Ning
- Hebei Key Lab of Optic-electronic Information and Materials, The College of Physics Science and Technology , Hebei University , Baoding 071002 , China
| | - Jingtian Zhou
- National Synchrotron Radiation Laboratory and CAS Key Laboratory of Materials for Energy Conversion , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Zhiping Bian
- National Synchrotron Radiation Laboratory and CAS Key Laboratory of Materials for Energy Conversion , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Zhenlin Luo
- National Synchrotron Radiation Laboratory and CAS Key Laboratory of Materials for Energy Conversion , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Chunyin Qiu
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology , Wuhan University , Wuhan 430072 , China
| | - Xing-Qiang Shi
- Department of Physics , Southern University of Science and Technology , Shenzhen 518055 , China
| | - Hongtao He
- Department of Physics , Southern University of Science and Technology , Shenzhen 518055 , China
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7
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Lan D, Chen B, Qu L, Jin F, Guo Z, Xu L, Zhang K, Gao G, Chen F, Jin S, Wang L, Wu W. Interfacial Engineering of Ferromagnetism in Epitaxial Manganite/Ruthenate Superlattices via Interlayer Chemical Doping. ACS APPLIED MATERIALS & INTERFACES 2019; 11:10399-10408. [PMID: 30775907 DOI: 10.1021/acsami.8b22055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Interfacial charge transfer and structural proximity effects are the two essential routes to trigger and tune numerous functionalities of perovskite oxide heterostructures. However, the cooperation and competition of these two interfacial effects in one epitaxial system have not been fully understood. Herein, we fabricate a series of La0.67Ca0.33MnO3/CaRuO3 superlattices and introduce various chemical doping in the nonmagnetic CaRuO3 interlayers. We found that Ti, Sr, and La doping in the CaRuO3 layer can effectively tune the interfacial charge transfer and octahedral rotation, thus modulating the ferromagnetism of the superlattices. Specifically, the B-site Ti doping depletes the Ru 4d band and suppresses the interfacial charge transfer, leading to a decay of ferromagnetic Curie temperature ( TC). In contrast, the A-site Sr doping maintains a sizable charge transfer and meanwhile suppresses the octahedral rotation, which facilitates ferromagnetism and significantly enhances the TC up to 291 K. The La doping turns out to localize the itinerant electrons in the CaRuO3 layer, which suppresses both the interfacial charge transfer and ferromagnetism. The observed intriguing interfacial engineering of magnetism would pave a new way to understand the collective effects of interfacial charge transfer and structural proximity on the physical properties of oxide heterostructures.
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Affiliation(s)
- Da Lan
- Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - Binbin Chen
- Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - LiLi Qu
- Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - Feng Jin
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory and Hefei Science Center , Chinese Academy of Sciences , Hefei 230031 , China
| | - Zhuang Guo
- Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - Liqiang Xu
- Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - Kexuan Zhang
- Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - Guanyin Gao
- Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - Feng Chen
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory and Hefei Science Center , Chinese Academy of Sciences , Hefei 230031 , China
| | - Shaowei Jin
- Institute of Physical Science and Information Technology , Anhui University , Hefei 230601 , China
| | - Lingfei Wang
- Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
| | - Wenbin Wu
- Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei 230026 , China
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory and Hefei Science Center , Chinese Academy of Sciences , Hefei 230031 , China
- Institute of Physical Science and Information Technology , Anhui University , Hefei 230601 , China
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8
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Dey U, Chatterjee S, Taraphder A. Antisite-disorder engineering in La-based oxide heterostructures via oxygen vacancy control. Phys Chem Chem Phys 2018; 20:17871-17880. [PMID: 29923559 DOI: 10.1039/c8cp01500g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
It has been realized lately that disorder, primarily in the form of oxygen vacancies, cation stoichiometry, atomic inter-diffusion and antisite defects, has a major effect on the electronic and transport properties of a 2D electron liquid at oxide hetero-interfaces - the first and the last being the two key players. In order to delineate the roles of these two key factors, we have investigated the effect of oxygen vacancies on the antisite disorder at a large number of interfaces separating two La-based transition metal oxides, using density functional theory. The oxygen vacancy is found to suppress antisite disorder in some heterostructures thereby stabilizing the ordered structure, while in some others, it tends to favor disorder, opening up the possibility of using it to control the order. Our calculations show that the oxygen vacancy offers an opportunity to generate new magnetic states by manipulating the inter-site coupling. Moreover, it can be used to control the electrical transport. The oxygen vacancy and antisite disorder are intrinsic to oxide heterostructures and it is therefore incumbent to engineer the latter and tune the magnetic and transport properties by controlling the oxygen partial pressure during growth.
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Affiliation(s)
- Urmimala Dey
- Centre for Theoretical Studies, Indian Institute of Technology, Kharagpur, India.
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9
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Chen H, Millis A. Design of new Mott multiferroics via complete charge transfer: promising candidates for bulk photovoltaics. Sci Rep 2017; 7:6142. [PMID: 28733597 PMCID: PMC5522466 DOI: 10.1038/s41598-017-06396-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 06/09/2017] [Indexed: 11/10/2022] Open
Abstract
Optimal materials to induce bulk photovoltaic effects should lack inversion symmetry and have an optical gap matching the energies of visible radiation. Ferroelectric perovskite oxides such as BaTiO3 and PbTiO3 exhibit substantial polarization and stability, but have the disadvantage of excessively large band gaps. We use both density functional theory and dynamical mean field theory calculations to design a new class of Mott multiferroics–double perovskite oxides A2VFeO6 (A = Ba, Pb, etc). While neither perovskite AVO3 nor AFeO3 is ferroelectric, in the double perovskite A2VFeO6 a ‘complete’ charge transfer from V to Fe leads to a non-bulk-like charge configuration–an empty V-d shell and a half-filled Fe-d shell, giving rise to a polarization comparable to that of ferroelectric ATiO3. Different from nonmagnetic ATiO3, the new double perovskite oxides have an antiferromagnetic ground state and around room temperatures, are paramagnetic Mott insulators. Most importantly, the V d0 state significantly reduces the band gap of A2VFeO6, making it smaller than that of ATiO3 and BiFeO3 and rendering the new multiferroics a promising candidate to induce bulk photovoltaic effects.
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Affiliation(s)
- Hanghui Chen
- NYU-ECNU Institute of Physics, NYU Shanghai, Shanghai, 200062, China. .,Department of Physics, New York University, New York, NY, 10002, USA.
| | - Andrew Millis
- Department of Physics, Columbia University, New York, NY, 10027, USA
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10
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Chen H, Millis A. Charge transfer driven emergent phenomena in oxide heterostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:243001. [PMID: 28437253 DOI: 10.1088/1361-648x/aa6efe] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Complex oxides exhibit many intriguing phenomena, including metal-insulator transition, ferroelectricity/multiferroicity, colossal magnetoresistance and high transition temperature superconductivity. Advances in epitaxial thin film growth techniques enable us to combine different complex oxides with atomic precision and form an oxide heterostructure. Recent theoretical and experimental work has shown that charge transfer across oxide interfaces generally occurs and leads to a great diversity of emergent interfacial properties which are not exhibited by bulk constituents. In this report, we review mechanisms and physical consequence of charge transfer across interfaces in oxide heterostructures. Both theoretical proposals and experimental measurements of various oxide heterostructures are discussed and compared. We also review the theoretical methods that are used to calculate charge transfer across oxide interfaces and discuss the success and challenges in theory. Finally, we present a summary and perspectives for future research.
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Affiliation(s)
- Hanghui Chen
- NYU-ECNU Institute of Physics, New York University Shanghai, 200062, People's Republic of China. Department of Physics, New York University, New York, NY 10002, United States of America
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11
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Díez-García MI, Gómez R. Metal Doping to Enhance the Photoelectrochemical Behavior of LaFeO 3 Photocathodes. CHEMSUSCHEM 2017; 10:2457-2463. [PMID: 28317341 DOI: 10.1002/cssc.201700166] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/16/2017] [Indexed: 06/06/2023]
Abstract
The development of tandem devices for water photosplitting requires the preparation of photocathodic materials based on earth-abundant elements that show long-term stability in aqueous electrolytes. Ternary metal oxides seem to be a viable option, among which perovskites stand out. In this context, transparent and compact LaFeO3 thin-film electrodes have been prepared by a sol-gel process, both undoped and doped with metals (M) such as Mg or Zn. Pristine electrodes support the development of cathodic photocurrents in 0.1 m NaOH aqueous solutions, particularly in the presence of oxygen, with an onset potential as high as 1.4 V versus the reversible hydrogen electrode. Doping with Mg or Zn leads to an important enhancement of the photocurrent, which peaks for a stoichiometry of LaFe0.95 M0.05 O3 with a sixfold enhancement with respect to the pristine material. Such an improvement is attributed to an increase in both the density and mobility of the majority carriers, although a contribution of surface passivation cannot be excluded.
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Affiliation(s)
- María Isabel Díez-García
- Departament de Química Física i Institut Universitari d'Electroquímica, Universitat d'Alacant, Apartat 99, E-, 03080, Alicante, Spain
| | - Roberto Gómez
- Departament de Química Física i Institut Universitari d'Electroquímica, Universitat d'Alacant, Apartat 99, E-, 03080, Alicante, Spain
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12
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Comes R, Chambers S. Interface Structure, Band Alignment, and Built-In Potentials at LaFeO_{3}/n-SrTiO_{3} Heterojunctions. PHYSICAL REVIEW LETTERS 2016; 117:226802. [PMID: 27925724 DOI: 10.1103/physrevlett.117.226802] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Indexed: 06/06/2023]
Abstract
Interface structure at polar-nonpolar interfaces has been shown to be a key factor in controlling emergent behavior in oxide heterostructures, including the LaFeO_{3}/n-SrTiO_{3} system. We demonstrate via high-energy-resolution x-ray photoemission that epitaxial LaFeO_{3}/n-SrTiO_{3}(001) heterojunctions engineered to have opposite interface polarities exhibit very similar band offsets and potential gradients within the LaFeO_{3} films. However, differences in the potential gradient within the SrTiO_{3} layer depending on polarity may promote hole diffusion into LaFeO_{3} for applications in photocatalysis.
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Affiliation(s)
- Ryan Comes
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
- Department of Physics, Auburn University, Auburn, Alabama 36849, USA
| | - Scott Chambers
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
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Weng Y, Lin L, Dagotto E, Dong S. Inversion of Ferrimagnetic Magnetization by Ferroelectric Switching via a Novel Magnetoelectric Coupling. PHYSICAL REVIEW LETTERS 2016; 117:037601. [PMID: 27472140 DOI: 10.1103/physrevlett.117.037601] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Indexed: 06/06/2023]
Abstract
Although several multiferroic materials or heterostructures have been extensively studied, finding strong magnetoelectric couplings for the electric field control of the magnetization remains challenging. Here, a novel interfacial magnetoelectric coupling based on three components (ferroelectric dipole, magnetic moment, and antiferromagnetic order) is analytically formulated. As an extension of carrier-mediated magnetoelectricity, the new coupling is shown to induce an electric-magnetic hysteresis loop. Realizations employing BiFeO_{3} bilayers grown along the [111] axis are proposed. Without involving magnetic phase transitions, the magnetization orientation can be switched by the carrier modulation driven by the field effect, as confirmed using first-principles calculations.
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Affiliation(s)
- Yakui Weng
- Department of Physics, Southeast University, Nanjing 211189, China
| | - Lingfang Lin
- Department of Physics, Southeast University, Nanjing 211189, China
| | - Elbio Dagotto
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Shuai Dong
- Department of Physics, Southeast University, Nanjing 211189, China
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Grisolia M, Varignon J, Sanchez-Santolino G, Arora A, Valencia S, Varela M, Abrudan R, Weschke E, Schierle E, Rault J, Rueff JP, Barthélémy A, Santamaria J, Bibes M. Hybridization-controlled charge transfer and induced magnetism at correlated oxide interfaces. NATURE PHYSICS 2016; 12:484-492. [PMID: 27158255 PMCID: PMC4856211 DOI: 10.1038/nphys3627] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 12/04/2015] [Indexed: 05/22/2023]
Abstract
At interfaces between conventional materials, band bending and alignment are classically controlled by differences in electrochemical potential. Applying this concept to oxides in which interfaces can be polar and cations may adopt a mixed valence has led to the discovery of novel two-dimensional states between simple band insulators such as LaAlO3 and SrTiO3. However, many oxides have a more complex electronic structure, with charge, orbital and/or spin orders arising from strong Coulomb interactions between transition metal and oxygen ions. Such electronic correlations offer a rich playground to engineer functional interfaces but their compatibility with the classical band alignment picture remains an open question. Here we show that beyond differences in electron affinities and polar effects, a key parameter determining charge transfer at correlated oxide interfaces is the energy required to alter the covalence of the metal-oxygen bond. Using the perovskite nickelate (RNiO3) family as a template, we probe charge reconstruction at interfaces with gadolinium titanate GdTiO3. X-ray absorption spectroscopy shows that the charge transfer is thwarted by hybridization effects tuned by the rare-earth (R) size. Charge transfer results in an induced ferromagnetic-like state in the nickelate, exemplifying the potential of correlated interfaces to design novel phases. Further, our work clarifies strategies to engineer two-dimensional systems through the control of both doping and covalence.
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Affiliation(s)
- M.N. Grisolia
- Unité Mixte de Physique CNRS/Thales, 1 avenue A. Fresnel, 91767 Palaiseau, France, and Université Paris-Sud, 91405 Orsay, France
| | - J. Varignon
- Unité Mixte de Physique CNRS/Thales, 1 avenue A. Fresnel, 91767 Palaiseau, France, and Université Paris-Sud, 91405 Orsay, France
| | - G. Sanchez-Santolino
- GFMC, Departamento Física Aplicada III, Universidad Complutense Madrid, 28040 Madrid, Spain, and Laboratorio de Heteroestructuras con aplicación en Spintronica, Unidad Asociada CSIC/Universidad Complutense de Madrid, Sor Juana Inés de la Cruz, 3, 28049 Madrid, Spain
| | - A. Arora
- Helmholtz-Zentrum Berlin für Materialen & Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - S. Valencia
- Helmholtz-Zentrum Berlin für Materialen & Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - M. Varela
- GFMC, Departamento Física Aplicada III, Universidad Complutense Madrid, 28040 Madrid, Spain, and Laboratorio de Heteroestructuras con aplicación en Spintronica, Unidad Asociada CSIC/Universidad Complutense de Madrid, Sor Juana Inés de la Cruz, 3, 28049 Madrid, Spain
- Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - R. Abrudan
- Helmholtz-Zentrum Berlin für Materialen & Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
- Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - E. Weschke
- Helmholtz-Zentrum Berlin für Materialen & Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - E. Schierle
- Helmholtz-Zentrum Berlin für Materialen & Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - J.E. Rault
- Synchrotron SOLEIL, L'Orme des Merisiers Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - J.-P. Rueff
- Synchrotron SOLEIL, L'Orme des Merisiers Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - A. Barthélémy
- Unité Mixte de Physique CNRS/Thales, 1 avenue A. Fresnel, 91767 Palaiseau, France, and Université Paris-Sud, 91405 Orsay, France
| | - J. Santamaria
- GFMC, Departamento Física Aplicada III, Universidad Complutense Madrid, 28040 Madrid, Spain, and Laboratorio de Heteroestructuras con aplicación en Spintronica, Unidad Asociada CSIC/Universidad Complutense de Madrid, Sor Juana Inés de la Cruz, 3, 28049 Madrid, Spain
| | - M. Bibes
- Unité Mixte de Physique CNRS/Thales, 1 avenue A. Fresnel, 91767 Palaiseau, France, and Université Paris-Sud, 91405 Orsay, France
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Comes RB, Kaspar TC, Heald SM, Bowden ME, Chambers SA. Infrared optical absorption in low-spin Fe(2+)-doped SrTiO3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:035901. [PMID: 26732030 DOI: 10.1088/0953-8984/28/3/035901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Band gap engineering in SrTiO3 and related titanate perovskites has long been explored due to the intriguing properties of the materials for photocatalysis and photovoltaic applications. A popular approach in the materials chemistry community is to substitutionally dope aliovalent transition metal ions onto the B site in the lattice to alter the valence band. However, in such a scheme there is limited control over the dopant valence, and compensating defects often form. Here we demonstrate a novel technique to controllably synthesize Fe(2+)- and Fe(3+)-doped SrTiO3 thin films without formation of compensating defects by co-doping with La(3+) ions on the A site. We stabilize Fe(2+)-doped films by doping with two La ions for every Fe dopant, and find that the Fe ions exhibit a low-spin electronic configuration, producing optical transitions in the near infrared regime and degenerate doping. The novel electronic states observed here offer a new avenue for band gap engineering in perovskites for photocatalytic and photovoltaic applications.
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Affiliation(s)
- Ryan B Comes
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA 99352, USA
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16
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Engineered Mott ground state in a LaTiO(3+δ)/LaNiO3 heterostructure. Nat Commun 2016; 7:10418. [PMID: 26791402 PMCID: PMC4735946 DOI: 10.1038/ncomms10418] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 12/09/2015] [Indexed: 11/08/2022] Open
Abstract
In pursuit of creating cuprate-like electronic and orbital structures, artificial heterostructures based on LaNiO3 have inspired a wealth of exciting experimental and theoretical results. However, to date there is a very limited experimental understanding of the electronic and orbital states emerging from interfacial charge transfer and their connections to the modified band structure at the interface. Towards this goal, we have synthesized a prototypical superlattice composed of a correlated metal LaNiO3 and a doped Mott insulator LaTiO3+δ, and investigated its electronic structure by resonant X-ray absorption spectroscopy combined with X-ray photoemission spectroscopy, electrical transport and theory calculations. The heterostructure exhibits interfacial charge transfer from Ti to Ni sites, giving rise to an insulating ground state with orbital polarization and eg orbital band splitting. Our findings demonstrate how the control over charge at the interface can be effectively used to create exotic electronic, orbital and spin states. Interfaces between two dissimilar transition metal oxides can exhibit emergent strongly correlated electronic and magnetic states due to charge transfer and electronic reconfiguration. Here, the authors synthesize and investigate an exotic Mott ground state in LaTiO3+δ/LaNiO3 heterostructures.
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Di Castro D, Cantoni C, Ridolfi F, Aruta C, Tebano A, Yang N, Balestrino G. High-T(c) Superconductivity at the Interface between the CaCuO2 and SrTiO3 Insulating Oxides. PHYSICAL REVIEW LETTERS 2015; 115:147001. [PMID: 26551817 DOI: 10.1103/physrevlett.115.147001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Indexed: 06/05/2023]
Abstract
At interfaces between complex oxides it is possible to generate electronic systems with unusual electronic properties, which are not present in the isolated oxides. One important example is the appearance of superconductivity at the interface between insulating oxides, although, until now, with very low T(c). We report the occurrence of high T(c) superconductivity in the bilayer CaCuO(2)/SrTiO(3), where both the constituent oxides are insulating. In order to obtain a superconducting state, the CaCuO(2)/SrTiO(3) interface must be realized between the Ca plane of CaCuO(2) and the TiO(2) plane of SrTiO(3). Only in this case can oxygen ions be incorporated in the interface Ca plane, acting as apical oxygen for Cu and providing holes to the CuO(2) planes. A detailed hole doping spatial profile can be obtained by scanning transmission electron microscopy and electron-energy-loss spectroscopy at the O K edge, clearly showing that the (super)conductivity is confined to about 1-2 CaCuO(2) unit cells close to the interface with SrTiO(3). The results obtained for the CaCuO(2)/SrTiO(3) interface can be extended to multilayered high T(c) cuprates, contributing to explaining the dependence of T(c) on the number of CuO(2) planes in these systems.
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Affiliation(s)
- D Di Castro
- Dipartimento di Ingegneria Civile e Ingegneria Informatica, Università di Roma Tor Vergata, Via del Politecnico 1, I-00133 Roma, Italy
- CNR-SPIN, Università di Roma Tor Vergata, Roma I-00133, Italy
| | - C Cantoni
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6116, USA
| | - F Ridolfi
- Dipartimento di Ingegneria Civile e Ingegneria Informatica, Università di Roma Tor Vergata, Via del Politecnico 1, I-00133 Roma, Italy
| | - C Aruta
- CNR-SPIN, Università di Roma Tor Vergata, Roma I-00133, Italy
| | - A Tebano
- Dipartimento di Ingegneria Civile e Ingegneria Informatica, Università di Roma Tor Vergata, Via del Politecnico 1, I-00133 Roma, Italy
- CNR-SPIN, Università di Roma Tor Vergata, Roma I-00133, Italy
| | - N Yang
- CNR-SPIN, Università di Roma Tor Vergata, Roma I-00133, Italy
- Facoltà di Ingegneria, Università degli studi Niccolò Cusano, Rome I-00166, Italy
| | - G Balestrino
- Dipartimento di Ingegneria Civile e Ingegneria Informatica, Università di Roma Tor Vergata, Via del Politecnico 1, I-00133 Roma, Italy
- CNR-SPIN, Università di Roma Tor Vergata, Roma I-00133, Italy
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18
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Chen Y, Trier F, Kasama T, Christensen DV, Bovet N, Balogh ZI, Li H, Thydén KTS, Zhang W, Yazdi S, Norby P, Pryds N, Linderoth S. Creation of high mobility two-dimensional electron gases via strain induced polarization at an otherwise nonpolar complex oxide interface. NANO LETTERS 2015; 15:1849-1854. [PMID: 25692804 DOI: 10.1021/nl504622w] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The discovery of two-dimensional electron gases (2DEGs) in SrTiO3-based heterostructures provides new opportunities for nanoelectronics. Herein, we create a new type of oxide 2DEG by the epitaxial-strain-induced polarization at an otherwise nonpolar perovskite-type interface of CaZrO3/SrTiO3. Remarkably, this heterointerface is atomically sharp and exhibits a high electron mobility exceeding 60,000 cm(2) V(-1) s(-1) at low temperatures. The 2DEG carrier density exhibits a critical dependence on the film thickness, in good agreement with the polarization induced 2DEG scheme.
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Affiliation(s)
- Yunzhong Chen
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
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