1
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Liu Y, Liu X, Su A, Gong C, Chen S, Xia L, Zhang C, Tao X, Li Y, Li Y, Sun T, Bu M, Shao W, Zhao J, Li X, Peng Y, Guo P, Han Y, Zhu Y. Revolutionizing the structural design and determination of covalent-organic frameworks: principles, methods, and techniques. Chem Soc Rev 2024; 53:502-544. [PMID: 38099340 DOI: 10.1039/d3cs00287j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Covalent organic frameworks (COFs) represent an important class of crystalline porous materials with designable structures and functions. The interconnected organic monomers, featuring pre-designed symmetries and connectivities, dictate the structures of COFs, endowing them with high thermal and chemical stability, large surface area, and tunable micropores. Furthermore, by utilizing pre-functionalization or post-synthetic functionalization strategies, COFs can acquire multifunctionalities, leading to their versatile applications in gas separation/storage, catalysis, and optoelectronic devices. Our review provides a comprehensive account of the latest advancements in the principles, methods, and techniques for structural design and determination of COFs. These cutting-edge approaches enable the rational design and precise elucidation of COF structures, addressing fundamental physicochemical challenges associated with host-guest interactions, topological transformations, network interpenetration, and defect-mediated catalysis.
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Affiliation(s)
- Yikuan Liu
- Center for Electron Microscopy, Institute for Frontier and Interdisciplinary Sciences, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Materials Science and Engineering and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
| | - Xiaona Liu
- National Engineering Research Center of Lower-Carbon Catalysis Technology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
| | - An Su
- Center for Electron Microscopy, Institute for Frontier and Interdisciplinary Sciences, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Materials Science and Engineering and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
| | - Chengtao Gong
- Center for Electron Microscopy, Institute for Frontier and Interdisciplinary Sciences, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Materials Science and Engineering and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
| | - Shenwei Chen
- Center for Electron Microscopy, Institute for Frontier and Interdisciplinary Sciences, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Materials Science and Engineering and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
| | - Liwei Xia
- Center for Electron Microscopy, Institute for Frontier and Interdisciplinary Sciences, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Materials Science and Engineering and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
| | - Chengwei Zhang
- Center for Electron Microscopy, Institute for Frontier and Interdisciplinary Sciences, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Materials Science and Engineering and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
| | - Xiaohuan Tao
- Center for Electron Microscopy, Institute for Frontier and Interdisciplinary Sciences, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Materials Science and Engineering and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
| | - Yue Li
- Institute of Intelligent Computing, Zhejiang Lab, Hangzhou 311121, China
| | - Yonghe Li
- Center for Electron Microscopy, Institute for Frontier and Interdisciplinary Sciences, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Materials Science and Engineering and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
| | - Tulai Sun
- Center for Electron Microscopy, Institute for Frontier and Interdisciplinary Sciences, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Materials Science and Engineering and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
| | - Mengru Bu
- Center for Electron Microscopy, Institute for Frontier and Interdisciplinary Sciences, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Materials Science and Engineering and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
| | - Wei Shao
- Center for Electron Microscopy, Institute for Frontier and Interdisciplinary Sciences, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Materials Science and Engineering and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
| | - Jia Zhao
- Center for Electron Microscopy, Institute for Frontier and Interdisciplinary Sciences, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Materials Science and Engineering and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
| | - Xiaonian Li
- Center for Electron Microscopy, Institute for Frontier and Interdisciplinary Sciences, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Materials Science and Engineering and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
| | - Yongwu Peng
- Center for Electron Microscopy, Institute for Frontier and Interdisciplinary Sciences, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Materials Science and Engineering and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
| | - Peng Guo
- National Engineering Research Center of Lower-Carbon Catalysis Technology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
- University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Yu Han
- School of Emergent Soft Matter, South China University of Technology, Guangzhou, China.
- King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
| | - Yihan Zhu
- Center for Electron Microscopy, Institute for Frontier and Interdisciplinary Sciences, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Materials Science and Engineering and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
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2
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Li Z, Li Y, Yin C. Manipulating Molecular Self-Assembly Process at the Solid-Liquid Interface Probed by Scanning Tunneling Microscopy. Polymers (Basel) 2023; 15:4176. [PMID: 37896420 PMCID: PMC10610993 DOI: 10.3390/polym15204176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 10/16/2023] [Accepted: 10/18/2023] [Indexed: 10/29/2023] Open
Abstract
The phenomenon of ordered self-assembly on solid substrates is a topic of interest in both fundamental surface science research and its applications in nanotechnology. The regulation and control of two-dimensional (2D) self-assembled supra-molecular structures on surfaces have been realized through applying external stimuli. By utilizing scanning tunneling microscopy (STM), researchers can investigate the detailed phase transition process of self-assembled monolayers (SAMs), providing insight into the interplay between intermolecular weak interactions and substrate-molecule interactions, which govern the formation of molecular self-assembly. This review will discuss the structural transition of self-assembly probed by STM in response to external stimuli and provide state-of-the-art methods such as tip-induced confinement for the alignment of SAM domains and selective chirality. Finally, we discuss the challenges and opportunities in the field of self-assembly and STM.
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Affiliation(s)
| | - Yanan Li
- School of Chemical Engineering, Anhui University of Science and Technology, Huainan 232001, China;
| | - Chengjie Yin
- School of Chemical Engineering, Anhui University of Science and Technology, Huainan 232001, China;
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3
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Gross N, Kuhs CT, Ostovar B, Chiang WY, Wilson KS, Volek TS, Faitz ZM, Carlin CC, Dionne JA, Zanni MT, Gruebele M, Roberts ST, Link S, Landes CF. Progress and Prospects in Optical Ultrafast Microscopy in the Visible Spectral Region: Transient Absorption and Two-Dimensional Microscopy. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:14557-14586. [PMID: 37554548 PMCID: PMC10406104 DOI: 10.1021/acs.jpcc.3c02091] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/24/2023] [Indexed: 08/10/2023]
Abstract
Ultrafast optical microscopy, generally employed by incorporating ultrafast laser pulses into microscopes, can provide spatially resolved mechanistic insight into scientific problems ranging from hot carrier dynamics to biological imaging. This Review discusses the progress in different ultrafast microscopy techniques, with a focus on transient absorption and two-dimensional microscopy. We review the underlying principles of these techniques and discuss their respective advantages and applicability to different scientific questions. We also examine in detail how instrument parameters such as sensitivity, laser power, and temporal and spatial resolution must be addressed. Finally, we comment on future developments and emerging opportunities in the field of ultrafast microscopy.
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Affiliation(s)
- Niklas Gross
- Department
of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Christopher T. Kuhs
- Army
Research Laboratory-South, U.S. Army DEVCOM, Houston, Texas 77005, United States
| | - Behnaz Ostovar
- Department
of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States
| | - Wei-Yi Chiang
- Department
of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Kelly S. Wilson
- Department
of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Tanner S. Volek
- Department
of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Zachary M. Faitz
- Department
of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Claire C. Carlin
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
| | - Jennifer A. Dionne
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
- Department
of Radiology, Molecular Imaging Program at Stanford (MIPS), Stanford University School of Medicine, Stanford, California 94305, United States
| | - Martin T. Zanni
- Department
of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Martin Gruebele
- Department
of Chemistry, University of Illinois at
Urbana−Champaign, Urbana, Illinois 61801, United States
- Department
of Physics, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Center
for Biophysics and Quantitative Biology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Sean T. Roberts
- Department
of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Stephan Link
- Department
of Chemistry, Rice University, Houston, Texas 77005, United States
- Department
of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States
| | - Christy F. Landes
- Department
of Chemistry, Rice University, Houston, Texas 77005, United States
- Department
of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States
- Department
of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
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4
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Luo Y, Martin-Jimenez A, Pisarra M, Martin F, Garg M, Kern K. Imaging and controlling coherent phonon wave packets in single graphene nanoribbons. Nat Commun 2023; 14:3484. [PMID: 37311753 DOI: 10.1038/s41467-023-39239-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 06/06/2023] [Indexed: 06/15/2023] Open
Abstract
The motion of atoms is at the heart of any chemical or structural transformation in molecules and materials. Upon activation of this motion by an external source, several (usually many) vibrational modes can be coherently coupled, thus facilitating the chemical or structural phase transformation. These coherent dynamics occur on the ultrafast timescale, as revealed, e.g., by nonlocal ultrafast vibrational spectroscopic measurements in bulk molecular ensembles and solids. Tracking and controlling vibrational coherences locally at the atomic and molecular scales is, however, much more challenging and in fact has remained elusive so far. Here, we demonstrate that the vibrational coherences induced by broadband laser pulses on a single graphene nanoribbon (GNR) can be probed by femtosecond coherent anti-Stokes Raman spectroscopy (CARS) when performed in a scanning tunnelling microscope (STM). In addition to determining dephasing (~440 fs) and population decay times (~1.8 ps) of the generated phonon wave packets, we are able to track and control the corresponding quantum coherences, which we show to evolve on time scales as short as ~70 fs. We demonstrate that a two-dimensional frequency correlation spectrum unequivocally reveals the quantum couplings between different phonon modes in the GNR.
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Affiliation(s)
- Yang Luo
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Alberto Martin-Jimenez
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Michele Pisarra
- INFN-LNF, Gruppo Collegato di Cosenza, Via P. Bucci, cubo 31C, 87036, Rende (CS), Italy
| | - Fernando Martin
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nano), Faraday 9, Cantoblanco, 28049, Madrid, Spain
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049, Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Manish Garg
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany.
| | - Klaus Kern
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
- Institut de Physique, Ecole Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
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5
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Liang K, Bi L, Zhu Q, Zhou H, Li S. Ultrafast Dynamics Revealed with Time-Resolved Scanning Tunneling Microscopy: A Review. ACS APPLIED OPTICAL MATERIALS 2023; 1:924-938. [PMID: 37260467 PMCID: PMC10227725 DOI: 10.1021/acsaom.2c00169] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 02/23/2023] [Indexed: 06/02/2023]
Abstract
A scanning tunneling microscope (STM) capable of performing pump-probe spectroscopy integrates unmatched atomic-scale resolution with high temporal resolution. In recent years, the union of electronic, terahertz, or visible/near-infrared pulses with STM has contributed to our understanding of the atomic-scale processes that happen between milliseconds and attoseconds. This time-resolved STM (TR-STM) technique is evolving into an unparalleled approach for exploring the ultrafast nuclear, electronic, or spin dynamics of molecules, low-dimensional structures, and material surfaces. Here, we review the recent advancements in TR-STM; survey its application in measuring the dynamics of three distinct systems, nucleus, electron, and spin; and report the studies on these transient processes in a series of materials. Besides the discussion on state-of-the-art techniques, we also highlight several emerging research topics about the ultrafast processes in nanoscale objects where we anticipate that the TR-STM can help broaden our knowledge.
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Affiliation(s)
- Kangkai Liang
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
- Materials
Science and Engineering Program, University
of California, San Diego, La Jolla, California 92093-0418, United States
| | - Liya Bi
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
- Materials
Science and Engineering Program, University
of California, San Diego, La Jolla, California 92093-0418, United States
| | - Qingyi Zhu
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
| | - Hao Zhou
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
- Materials
Science and Engineering Program, University
of California, San Diego, La Jolla, California 92093-0418, United States
| | - Shaowei Li
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
- Materials
Science and Engineering Program, University
of California, San Diego, La Jolla, California 92093-0418, United States
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6
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Kurihara T, Yang T, Mizuno T, Kanai T, Itatani J. Highly CEP-stable optical parametric amplifier at 2 µm with a few-cycle duration and 100 kHz repetition rate. OPTICS EXPRESS 2023; 31:11649-11658. [PMID: 37155795 DOI: 10.1364/oe.481126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We develop a BiB3O6 (BiBO)-based optical parametric amplifier in the spectral region around 2 µm using a Yb:KGW amplifier operating at 100 kHz. The two-stage degenerate optical parametric amplification results in a typical output energy of 30 µJ after compression, spectrum covering 1.7-2.5 µm range, and a pulse duration fully compressible down to 16.4 fs, corresponding to 2.3 cycles. Due to the inline difference frequency generation of the seed pulses, the carrier envelope phase (CEP) is passively stabilized without feedback over 11 hours at the level below 100 mrad including a long-term drift. Short-term statistical analysis in the spectral domain further shows a behavior qualitatively different from that of parametric fluorescence, indicating high degree of suppression of optical parametric fluorescence. The high phase stability together with the few-cycle pulse duration is promising for the investigation of high-field phenomena such as subcycle spectroscopy in solids or high harmonics generation.
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7
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Wang L, Bai D, Xia Y, Ho W. Electrical Manipulation of Quantum Coherence in a Two-Level Molecular System. PHYSICAL REVIEW LETTERS 2023; 130:096201. [PMID: 36930940 DOI: 10.1103/physrevlett.130.096201] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 01/06/2023] [Indexed: 06/18/2023]
Abstract
We report the manipulation of ultrafast quantum coherence of a two-level single hydrogen molecular system by employing static electric field from the sample bias in a femtosecond terahertz scanning tunneling microscope. A H_{2} molecule adsorbed on the polar Cu_{2}N surface develops an electric dipole and exhibits a giant Stark effect. An avoided crossing of the quantum state energy levels is derived from the resonant frequency of the single H_{2} two levels in a double-well potential. The dephasing time of the initial wave packet can also be changed by applying the electric field. The electrical manipulation for different tunneling gaps in three dimensions allows quantification of the surface electrostatic fields at the atomic scale. Our work demonstrated the potential application of molecules as controllable two-level molecular systems.
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Affiliation(s)
- Likun Wang
- Department of Physics and Astronomy, University of California, Irvine, Irvine, California 92697-4575, USA
| | - Dan Bai
- Department of Physics and Astronomy, University of California, Irvine, Irvine, California 92697-4575, USA
| | - Yunpeng Xia
- Department of Physics and Astronomy, University of California, Irvine, Irvine, California 92697-4575, USA
| | - W Ho
- Department of Physics and Astronomy, University of California, Irvine, Irvine, California 92697-4575, USA
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, USA
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8
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Traeger GA, Teichmann MH, Schröder B, Wenderoth M. Combining grating-coupled illumination and image recognition for stable and localized optical scanning tunneling microscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:023702. [PMID: 36859060 DOI: 10.1063/5.0123604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 01/07/2023] [Indexed: 06/18/2023]
Abstract
Combining scanning tunneling microscopy (STM) and optical excitation has been a major objective in STM for the last 30 years to study light-matter interactions on the atomic scale. The combination with modern pulsed laser systems even made it possible to achieve a temporal resolution down to the femtosecond regime. A promising approach toward a truly localized optical excitation is featured by nanofocusing via an optical antenna spatially separated from the tunnel junction. Until now, these experiments have been limited by thermal instabilities introduced by the laser. This paper presents a versatile solution to this problem by actively coupling the laser and STM, bypassing the vibration-isolation without compromising it. We utilize optical image recognition to monitor the position of the tunneling junction and compensate for any movement of the microscope relative to the laser setup with up to 10 Hz by adjusting the beamline. Our setup stabilizes the focus position with high precision (<1 μm) on long timescales (>1 h) and allows for high resolution STM under intense optical excitation with femtosecond pulses.
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Affiliation(s)
- Georg A Traeger
- IV. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Lower Saxony, Germany
| | - Marlo H Teichmann
- IV. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Lower Saxony, Germany
| | - Benjamin Schröder
- IV. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Lower Saxony, Germany
| | - Martin Wenderoth
- IV. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Lower Saxony, Germany
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9
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Liu S, Hammud A, Hamada I, Wolf M, Müller M, Kumagai T. Nanoscale coherent phonon spectroscopy. SCIENCE ADVANCES 2022; 8:eabq5682. [PMID: 36269832 PMCID: PMC9586471 DOI: 10.1126/sciadv.abq5682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 09/02/2022] [Indexed: 06/02/2023]
Abstract
Coherent phonon spectroscopy can provide microscopic insight into ultrafast lattice dynamics and its coupling to other degrees of freedom under nonequilibrium conditions. Ultrafast optical spectroscopy is a well-established method to study coherent phonons, but the diffraction limit has hampered observing their local dynamics directly. Here, we demonstrate nanoscale coherent phonon spectroscopy using ultrafast laser-induced scanning tunneling microscopy in a plasmonic junction. Coherent phonons are locally excited in ultrathin zinc oxide films by the tightly confined plasmonic field and are probed via the photoinduced tunneling current through an electronic resonance of the zinc oxide film. Concurrently performed tip-enhanced Raman spectroscopy allows us to identify the involved phonon modes. In contrast to the Raman spectra, the phonon dynamics observed in coherent phonon spectroscopy exhibit strong nanoscale spatial variations that are correlated with the distribution of the electronic local density of states resolved by scanning tunneling spectroscopy.
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Affiliation(s)
- Shuyi Liu
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Adnan Hammud
- Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Ikutaro Hamada
- Department of Precision Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-Oka, Suita, Osaka 565-0871, Japan
| | - Martin Wolf
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Melanie Müller
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Takashi Kumagai
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
- Center for Mesoscopic Sciences, Institute for Molecular Science, Okazaki 444-8585, Japan
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10
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Martín Sabanés N, Krecinic F, Kumagai T, Schulz F, Wolf M, Müller M. Femtosecond Thermal and Nonthermal Hot Electron Tunneling Inside a Photoexcited Tunnel Junction. ACS NANO 2022; 16:14479-14489. [PMID: 36027581 PMCID: PMC9527804 DOI: 10.1021/acsnano.2c04846] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 08/19/2022] [Indexed: 06/02/2023]
Abstract
Efficient operation of electronic nanodevices at ultrafast speeds requires understanding and control of the currents generated by femtosecond bursts of light. Ultrafast laser-induced currents in metallic nanojunctions can originate from photoassisted hot electron tunneling or lightwave-induced tunneling. Both processes can drive localized photocurrents inside a scanning tunneling microscope (STM) on femto- to attosecond time scales, enabling ultrafast STM with atomic spatial resolution. Femtosecond laser excitation of a metallic nanojunction, however, also leads to the formation of a transient thermalized electron distribution, but the tunneling of thermalized hot electrons on time scales faster than electron-lattice equilibration is not well understood. Here, we investigate ultrafast electronic heating and transient thermionic tunneling inside a metallic photoexcited tunnel junction and its role in the generation of ultrafast photocurrents in STM. Phase-resolved sampling of broadband terahertz (THz) pulses via the THz-field-induced modulation of ultrafast photocurrents allows us to probe the electronic temperature evolution inside the STM tip and to observe the competition between instantaneous and delayed tunneling due to nonthermal and thermal hot electron distributions in real time. Our results reveal the pronounced nonthermal character of photoinduced hot electron tunneling and provide a detailed microscopic understanding of hot electron dynamics inside a laser-excited tunnel junction.
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Affiliation(s)
- Natalia Martín Sabanés
- Department
of Physical Chemistry, Fritz Haber Institute
of the Max Planck Society, Faradayweg 4-6, 14195Berlin, Germany
- IMDEA
Nanoscience, Faraday 9, 28049Madrid, Spain
| | - Faruk Krecinic
- Department
of Physical Chemistry, Fritz Haber Institute
of the Max Planck Society, Faradayweg 4-6, 14195Berlin, Germany
| | - Takashi Kumagai
- Department
of Physical Chemistry, Fritz Haber Institute
of the Max Planck Society, Faradayweg 4-6, 14195Berlin, Germany
- Center
for Mesoscopic Sciences, Institute for Molecular
Science, 444-8585Okazaki, Japan
| | - Fabian Schulz
- Department
of Physical Chemistry, Fritz Haber Institute
of the Max Planck Society, Faradayweg 4-6, 14195Berlin, Germany
| | - Martin Wolf
- Department
of Physical Chemistry, Fritz Haber Institute
of the Max Planck Society, Faradayweg 4-6, 14195Berlin, Germany
| | - Melanie Müller
- Department
of Physical Chemistry, Fritz Haber Institute
of the Max Planck Society, Faradayweg 4-6, 14195Berlin, Germany
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11
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Luo Y, Martin-Jimenez A, Gutzler R, Garg M, Kern K. Ultrashort Pulse Excited Tip-Enhanced Raman Spectroscopy in Molecules. NANO LETTERS 2022; 22:5100-5106. [PMID: 35704454 PMCID: PMC9284611 DOI: 10.1021/acs.nanolett.2c00485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Vibrational fingerprints of molecules and low-dimension materials can be traced with subnanometer resolution by performing Tip-enhanced Raman spectroscopy (TERS) in a scanning tunneling microscope (STM). Strong atomic-scale localization of light in the plasmonic nanocavity of the STM enables high spatial resolution in STM-TERS; however, the temporal resolution is so far limited. Here, we demonstrate stable TERS measurements from subphthalocyanine (SubPc) molecules excited by ∼500 fs long laser pulses in a low-temperature (LT) ultrahigh-vacuum (UHV) STM. The intensity of the TERS signal excited with ultrashort pulses scales linearly with the increasing flux of the laser pulses and exponentially with the decreasing gap-size of the plasmonic nanocavity. Furthermore, we compare the characteristic features of TERS excited with ultrashort pulses and with a continuous-wave (CW) laser. Our work lays the foundation for future experiments of time-resolved femtosecond TERS for the investigation of molecular dynamics with utmost spatial, temporal, and energy resolutions simultaneously.
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Affiliation(s)
- Yang Luo
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - Alberto Martin-Jimenez
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - Rico Gutzler
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - Manish Garg
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - Klaus Kern
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
- Institut
de Physique, Ecole Polytechnique Fédérale
de Lausanne, 1015 Lausanne, Switzerland
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