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Yuan Y, Patel RK, Banik S, Reta TB, Bisht RS, Fong DD, Sankaranarayanan SKRS, Ramanathan S. Proton Conducting Neuromorphic Materials and Devices. Chem Rev 2024. [PMID: 39038231 DOI: 10.1021/acs.chemrev.4c00071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Neuromorphic computing and artificial intelligence hardware generally aims to emulate features found in biological neural circuit components and to enable the development of energy-efficient machines. In the biological brain, ionic currents and temporal concentration gradients control information flow and storage. It is therefore of interest to examine materials and devices for neuromorphic computing wherein ionic and electronic currents can propagate. Protons being mobile under an external electric field offers a compelling avenue for facilitating biological functionalities in artificial synapses and neurons. In this review, we first highlight the interesting biological analog of protons as neurotransmitters in various animals. We then discuss the experimental approaches and mechanisms of proton doping in various classes of inorganic and organic proton-conducting materials for the advancement of neuromorphic architectures. Since hydrogen is among the lightest of elements, characterization in a solid matrix requires advanced techniques. We review powerful synchrotron-based spectroscopic techniques for characterizing hydrogen doping in various materials as well as complementary scattering techniques to detect hydrogen. First-principles calculations are then discussed as they help provide an understanding of proton migration and electronic structure modification. Outstanding scientific challenges to further our understanding of proton doping and its use in emerging neuromorphic electronics are pointed out.
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Affiliation(s)
- Yifan Yuan
- Department of Electrical & Computer Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Ranjan Kumar Patel
- Department of Electrical & Computer Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Suvo Banik
- Department of Mechanical and Industrial Engineering, University of Illinois, Chicago, Illinois 60607, United States
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Tadesse Billo Reta
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Ravindra Singh Bisht
- Department of Electrical & Computer Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Dillon D Fong
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Subramanian K R S Sankaranarayanan
- Department of Mechanical and Industrial Engineering, University of Illinois, Chicago, Illinois 60607, United States
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Shriram Ramanathan
- Department of Electrical & Computer Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
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Hwang IH, Park CI, Yeo S, Sun CJ, Han SW. Decoupling the metal insulator transition and crystal field effects of VO 2. Sci Rep 2021; 11:3135. [PMID: 33542342 PMCID: PMC7862372 DOI: 10.1038/s41598-021-82588-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/18/2021] [Indexed: 11/08/2022] Open
Abstract
VO2 is a highly correlated electron system which has a metal-to-insulator transition (MIT) with a dramatic change of conductivity accompanied by a first-order structural phase transition (SPT) near room temperature. The origin of the MIT is still controversial and there is ongoing debate over whether an SPT induces the MIT and whether the Tc can be engineered using artificial parameters. We examined the electrical and local structural properties of Cr- and Co-ion implanted VO2 (Cr-VO2 and Co-VO2) films using temperature-dependent resistance and X-ray absorption fine structure (XAFS) measurements at the V K edge. The temperature-dependent electrical resistance measurements of both Cr-VO2 and Co-VO2 films showed sharp MIT features. The Tc values of the Cr-VO2 and Co-VO2 films first decreased and then increased relative to that of pristine VO2 as the ion flux was increased. The pre-edge peak of the V K edge from the Cr-VO2 films with a Cr ion flux ≥ 1013 ions/cm2 showed no temperature-dependent behavior, implying no changes in the local density of states of V 3d t2g and eg orbitals during MIT. Extended XAFS (EXAFS) revealed that implanted Cr and Co ions and their tracks caused a substantial amount of structural disorder and distortion at both vanadium and oxygen sites. The resistance and XAFS measurements revealed that VO2 experiences a sharp MIT when the distance of V-V pairs undergoes an SPT without any transitions in either the VO6 octahedrons or the V 3d t2g and eg states. This indicates that the MIT of VO2 occurs with no changes of the crystal fields.
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Affiliation(s)
- In-Hui Hwang
- Department of Physics Education, Institute of Fusion Science, and Institute of Science Education, Jeonbuk National University, Jeonju, 54896, Korea
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Chang-In Park
- Department of Physics Education, Institute of Fusion Science, and Institute of Science Education, Jeonbuk National University, Jeonju, 54896, Korea
| | - Sunmog Yeo
- Korea Atomic Energy Research Institute, KOMAC, Miraero 181, Gyoungju, 38180, Korea
| | - Cheng-Jun Sun
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Sang-Wook Han
- Department of Physics Education, Institute of Fusion Science, and Institute of Science Education, Jeonbuk National University, Jeonju, 54896, Korea.
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Suleiman AO, Mansouri S, Émond N, Le Drogoff B, Bégin T, Margot J, Chaker M. Probing the role of thermal vibrational disorder in the SPT of VO[Formula: see text] by Raman spectroscopy. Sci Rep 2021; 11:1620. [PMID: 33452287 PMCID: PMC7810880 DOI: 10.1038/s41598-020-79758-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 12/09/2020] [Indexed: 11/09/2022] Open
Abstract
Phase competition in transition metal oxides has attracted remarkable interest for fundamental aspects and technological applications. Here, we report a concurrent study of the phase transitions in undoped and Cr-doped VO[Formula: see text] thin films. The structural, morphological and electrical properties of our films are examined and the microstructural effect on the metal-insulator transition (MIT) are highlighted. We further present a distinctive approach for analyzing the Raman data of undoped and Cr-doped VO[Formula: see text] thin films as a function of temperature, which are quantitatively correlated to the electrical measurements of VO[Formula: see text] films to give an insight into the coupling between the structural phase transition (SPT) and the MIT. These data are also combined with reported EXAFS measurements and a connection between the Raman intensities and the mean Debye-Waller factors [Formula: see text] is established. We found that the temperature dependence of the [Formula: see text] as calculated from the Raman intensity retraces the temperature profile of the [Formula: see text] as obtained from the EXAFS data analysis. Our findings provide an evidence on the critical role of the thermal vibrational disorder in the VO[Formula: see text] phase transitions. Our study demonstrates that correlating Raman data with EXAFS analysis, the lattice and electronic structural dynamics can be probed.
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Affiliation(s)
- Aminat Oyiza Suleiman
- Institut National de la Recherche Scientifique, Énergie Matériaux Télécommunications, 1650, Boulevard Lionel-Boulet, Varennes, QC J3X 1S2 Canada
| | - Sabeur Mansouri
- Institut National de la Recherche Scientifique, Énergie Matériaux Télécommunications, 1650, Boulevard Lionel-Boulet, Varennes, QC J3X 1S2 Canada
| | - Nicolas Émond
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
| | - Boris Le Drogoff
- Institut National de la Recherche Scientifique, Énergie Matériaux Télécommunications, 1650, Boulevard Lionel-Boulet, Varennes, QC J3X 1S2 Canada
| | - Théophile Bégin
- Département de Physique, Complexe des Sciences, Université de Montréal, 1375 Avenue Thérèse-Lavoie-Roux, Montréal, QC H2V 0B3 Canada
| | - Joëlle Margot
- Département de Physique, Complexe des Sciences, Université de Montréal, 1375 Avenue Thérèse-Lavoie-Roux, Montréal, QC H2V 0B3 Canada
| | - Mohamed Chaker
- Institut National de la Recherche Scientifique, Énergie Matériaux Télécommunications, 1650, Boulevard Lionel-Boulet, Varennes, QC J3X 1S2 Canada
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