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Lee H, Ahn JY, Chun SH, Cho DH, Sung D, Jung C, Shin J, Hwang J, Ha SS, Jang H, Cho BG, Kim S, Park J, Nam D, Eom I, Shim JH, Noh DY, Ihm Y, Song C. Observing femtosecond orbital dynamics in ultrafast Ge melting with time-resolved resonant X-ray scattering. IUCRJ 2023; 10:700-707. [PMID: 37772598 PMCID: PMC10619452 DOI: 10.1107/s2052252523007935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 09/11/2023] [Indexed: 09/30/2023]
Abstract
Photoinduced nonequilibrium phase transitions have stimulated interest in the dynamic interactions between electrons and crystalline ions, which have long been overlooked within the Born-Oppenheimer approximation. Ultrafast melting before lattice thermalization prompted researchers to revisit this issue to understand ultrafast photoinduced weakening of the crystal bonding. However, the absence of direct evidence demonstrating the role of orbital dynamics in lattice disorder leaves it elusive. By performing time-resolved resonant X-ray scattering with an X-ray free-electron laser, we directly monitored the ultrafast dynamics of bonding orbitals of Ge to drive photoinduced melting. Increased photoexcitation of bonding electrons amplifies the orbital disturbance to expedite the lattice disorder approaching the sub-picosecond scale of the nonthermal regime. The lattice disorder time shows strong nonlinear dependence on the laser fluence with a crossover behavior from thermal-driven to nonthermal-dominant kinetics, which is also verified by ab initio and two-temperature molecular dynamics simulations. This study elucidates the impact of bonding orbitals on lattice stability with a unifying interpretation on photoinduced melting.
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Affiliation(s)
- Heemin Lee
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Center for Ultrafast Science in Quantum Matter, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Republic of Korea
- Photon Science Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Je Young Ahn
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Sae Hwan Chun
- Photon Science Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Pohang Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Do Hyung Cho
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Center for Ultrafast Science in Quantum Matter, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Republic of Korea
| | - Daeho Sung
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Center for Ultrafast Science in Quantum Matter, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Republic of Korea
| | - Chulho Jung
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Center for Ultrafast Science in Quantum Matter, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Republic of Korea
| | - Jaeyong Shin
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Center for Ultrafast Science in Quantum Matter, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Republic of Korea
- Photon Science Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Junha Hwang
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Center for Ultrafast Science in Quantum Matter, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Republic of Korea
- Photon Science Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Sung Soo Ha
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Hoyoung Jang
- Photon Science Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Pohang Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Byeong-Gwan Cho
- Pohang Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Sunam Kim
- Pohang Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Jaeku Park
- Pohang Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Daewoong Nam
- Photon Science Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Pohang Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Intae Eom
- Photon Science Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Pohang Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Ji Hoon Shim
- Photon Science Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Do Young Noh
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
- Institute for Basic Science, Daejeon 34126, Republic of Korea
| | - Yungok Ihm
- Photon Science Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Changyong Song
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Center for Ultrafast Science in Quantum Matter, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Republic of Korea
- Photon Science Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
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2
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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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3
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Dong T, Zhang SJ, Wang NL. Recent Development of Ultrafast Optical Characterizations for Quantum Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022:e2110068. [PMID: 35853841 DOI: 10.1002/adma.202110068] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 06/09/2022] [Indexed: 06/15/2023]
Abstract
The advent of intense ultrashort optical pulses spanning a frequency range from terahertz to the visible has opened a new era in the experimental investigation and manipulation of quantum materials. The generation of strong optical field in an ultrashort time scale enables the steering of quantum materials nonadiabatically, inducing novel phenomenon or creating new phases which may not have an equilibrium counterpart. Ultrafast time-resolved optical techniques have provided rich information and played an important role in characterization of the nonequilibrium and nonlinear properties of solid systems. Here, some of the recent progress of ultrafast optical techniques and their applications to the detection and manipulation of physical properties in selected quantum materials are reviewed. Specifically, the new development in the detection of the Higgs mode and photoinduced nonequilibrium response in the study of superconductors by time-resolved terahertz spectroscopy are discussed.
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Affiliation(s)
- Tao Dong
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
| | - Si-Jie Zhang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
| | - Nan-Lin Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
- Beijing Academy of Quantum Information Sciences, Beijing, 100913, China
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4
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Kumar G, Chung PW. Selective Phonon Stimulation Mechanism to Tune Thermal Transport. ACS OMEGA 2022; 7:12787-12794. [PMID: 35474781 PMCID: PMC9026079 DOI: 10.1021/acsomega.1c07364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 03/28/2022] [Indexed: 06/14/2023]
Abstract
In this paper, we determine the degree to which changes can be induced in the equilibrium thermal diffusivity and conductivity of a material via a selective nonequilibrium infrared stimulation mechanism for phonons. Using the molecular crystal RDX, we use detailed momentum-dependent coupling information across the entire Brillouin zone and the phonon gas model to show that stimulating selected modes in the spectrum of a target material can induce substantial changes in the overall thermal transport properties. Specifically in the case of RDX, stimulating modes at ∼22.74 cm-1 over a linewidth of 1 cm-1 can lead to enhanced scattering rates that reduce the overall thermal diffusivity and conductivity by 15.58 and 12.46%, respectively, from their equilibrium values. Due to the rich spectral content in the materials, however, stimulating modes near ∼1140.67 cm-1 over a similar bandwidth can produce an increase in the thermal diffusivity and conductivity by 55.73 and 144.07%, respectively. The large changes suggest a mechanism to evoke substantially modulated thermal transport properties through light-matter interaction.
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5
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Vinod M, Raghavan G, Sivasubramanian V. Fano resonance between coherent acoustic phonon oscillations and electronic states near the bandgap of photoexcited GaAs. Sci Rep 2018; 8:17706. [PMID: 30532007 PMCID: PMC6286371 DOI: 10.1038/s41598-018-35866-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 10/31/2018] [Indexed: 11/09/2022] Open
Abstract
Impulsive photo-excitation of solids results in a travelling strain pulse which manifests itself as coherent acoustic phonon oscillations. These oscillations have been extensively studied using time-resolved pump-probe spectroscopy. In the present work, we report the generation of extremely long-lived, coherent longitudinal acoustic phonon oscillations in intrinsic GaAs (100), with clear and unambiguous evidence of Fano interference between these oscillations and the continuum of electronic states close to the bandgap. Fano resonance is a widespread phenomenon observed in atomic systems and condensed media that arises from quantum interference between a continuum of quantum states and a discrete quantum state. Among other techniques, Fano resonance has been investigated with respect to optical phonons studied with Raman Spectroscopy. In the present work, we investigate Fano resonance in coherent phonon oscillations generated without the aid of any capping layer, dopants or substrate/interface effects. Since Fano resonance is sensitive to changes in electronic structure, doping and defects, these observations are important to the field of picosecond ultrasonics which is used for non-destructive depth profiling of solids and for carrier diffusion studies.
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Affiliation(s)
- M Vinod
- Materials Science Group Indira Gandhi Centre for Atomic Research, Kalpakkam, 603 102, Tamil Nadu, India
| | - G Raghavan
- Materials Science Group Indira Gandhi Centre for Atomic Research, Kalpakkam, 603 102, Tamil Nadu, India. .,Homi Bhabha National Institute, Mumbai, India.
| | - V Sivasubramanian
- Materials Science Group Indira Gandhi Centre for Atomic Research, Kalpakkam, 603 102, Tamil Nadu, India.,Homi Bhabha National Institute, Mumbai, India
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6
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Ultrafast magnetization modulation induced by the electric field component of a terahertz pulse in a ferromagnetic-semiconductor thin film. Sci Rep 2018; 8:6901. [PMID: 29720716 PMCID: PMC5931997 DOI: 10.1038/s41598-018-25266-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 04/13/2018] [Indexed: 11/18/2022] Open
Abstract
High-speed magnetization control of ferromagnetic films using light pulses is attracting considerable attention and is increasingly important for the development of spintronic devices. Irradiation with a nearly monocyclic terahertz pulse, which can induce strong electromagnetic fields in ferromagnetic films within an extremely short time of less than ~1 ps, is promising for damping-free high-speed coherent control of the magnetization. Here, we successfully observe a terahertz response in a ferromagnetic-semiconductor thin film. In addition, we find that a similar terahertz response is observed even in a non-magnetic semiconductor and reveal that the electric-field component of the terahertz pulse plays a crucial role in the magnetization response through the spin-carrier interactions in a ferromagnetic-semiconductor thin film. Our findings will provide new guidelines for designing materials suitable for ultrafast magnetization reversal.
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7
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Wang MC, Qiao S, Jiang Z, Luo SN, Qi J. Wang et al. Reply. PHYSICAL REVIEW LETTERS 2016; 117:169702. [PMID: 27792357 DOI: 10.1103/physrevlett.117.169702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Indexed: 06/06/2023]
Affiliation(s)
- M C Wang
- The Peac Institute of Multiscale Sciences, Sichuan 610031, China
- Key Laboratory of Advanced Technologies of Materials, Southwest Jiaotong University, Sichuan 610031, China
| | - S Qiao
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
| | - Z Jiang
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - S N Luo
- The Peac Institute of Multiscale Sciences, Sichuan 610031, China
- Key Laboratory of Advanced Technologies of Materials, Southwest Jiaotong University, Sichuan 610031, China
| | - J Qi
- The Peac Institute of Multiscale Sciences, Sichuan 610031, China
- Key Laboratory of Advanced Technologies of Materials, Southwest Jiaotong University, Sichuan 610031, China
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8
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Coherent optical phonon oscillation and possible electronic softening in WTe2 crystals. Sci Rep 2016; 6:30487. [PMID: 27457385 PMCID: PMC4960623 DOI: 10.1038/srep30487] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 07/06/2016] [Indexed: 11/09/2022] Open
Abstract
A rapidly-growing interest in WTe2 has been triggered by the giant magnetoresistance effect discovered in this unique system. While many efforts have been made towards uncovering the electron- and spin-relevant mechanisms, the role of lattice vibration remains poorly understood. Here, we study the coherent vibrational dynamics in WTe2 crystals by using ultrafast pump-probe spectroscopy. The oscillation signal in time domain in WTe2 has been ascribed as due to the coherent dynamics of the lowest energy A1 optical phonons with polarization- and wavelength-dependent measurements. With increasing temperature, the phonon energy decreases due to anharmonic decay of the optical phonons into acoustic phonons. Moreover, a significant drop (15%) of the phonon energy with increasing pump power is observed which is possibly caused by the lattice anharmonicity induced by electronic excitation and phonon-phonon interaction.
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9
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Makino K, Saito Y, Fons P, Kolobov AV, Nakano T, Tominaga J, Hase M. Anisotropic lattice response induced by a linearly-polarized femtosecond optical pulse excitation in interfacial phase change memory material. Sci Rep 2016; 6:19758. [PMID: 26805401 PMCID: PMC4726132 DOI: 10.1038/srep19758] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 12/17/2015] [Indexed: 11/29/2022] Open
Abstract
Optical excitation of matter with linearly-polarized femtosecond pulses creates a transient non-equilibrium lattice displacement along a certain direction. Here, the pump and probe pulse polarization dependence of the photo-induced ultrafast lattice dynamics in (GeTe)2/(Sb2Te3)4 interfacial phase change memory material is investigated under obliquely incident conditions. Drastic pump polarization dependence of the coherent phonon amplitude is observed when the probe polarization angle is parallel to the c–axis of the sample, while the pump polarization dependence is negligible when the probe polarization angle is perpendicular to the c–axis. The enhancement of phonon oscillation amplitude due to pump polarization rotation for a specific probe polarization angle is only found in the early time stage (≤2 ps). These results indicate that the origin of the pump and probe polarization dependence is dominantly attributable to the anisotropically-formed photo-excited carriers which cause the directional lattice dynamics.
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Affiliation(s)
- Kotaro Makino
- Nanoelectronics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba 305-8565, Japan.,CREST, JST, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Yuta Saito
- Nanoelectronics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba 305-8565, Japan.,CREST, JST, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Paul Fons
- Nanoelectronics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba 305-8565, Japan.,CREST, JST, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Alexander V Kolobov
- Nanoelectronics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba 305-8565, Japan.,CREST, JST, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Takashi Nakano
- Nanoelectronics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba 305-8565, Japan.,CREST, JST, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Junji Tominaga
- Nanoelectronics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba 305-8565, Japan.,CREST, JST, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Muneaki Hase
- CREST, JST, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.,Division of Applied Physics, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8573, Japan
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10
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Observation of T₂-like coherent optical phonons in epitaxial Ge₂Sb₂Te₅/GaSb(001) films. Sci Rep 2013; 3:2965. [PMID: 24129388 PMCID: PMC3797426 DOI: 10.1038/srep02965] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 09/26/2013] [Indexed: 11/23/2022] Open
Abstract
The phonon spectrum of Ge2Sb2Te5 is a signature of its crystallographic structure and underlies the phase transition process used in memory applications. Epitaxial materials allow coherent optical phonons to be studied in femtosecond anisotropic reflectance measurements. A dominant phonon mode with frequency of 3.4 THz has been observed in epitaxial Ge2Sb2Te5 grown on GaSb(001). The dependence of signal strength upon pump and probe polarization is described by a theory of transient stimulated Raman scattering that accounts for the symmetry of the crystallographic structure through use of the Raman tensor. The 3.4 THz mode has the character of the 3 dimensional T2 mode expected for the Oh point group, confirming that the underlying crystallographic structure is cubic. New modes are observed in both Ge2Sb2Te5 and GaSb after application of large pump fluences, and are interpreted as 1 and 2 dimensional modes associated with segregation of Sb.
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11
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Kim JH, Nugraha A, Booshehri L, Hároz E, Sato K, Sanders G, Yee KJ, Lim YS, Stanton C, Saito R, Kono J. Coherent phonons in carbon nanotubes and graphene. Chem Phys 2013. [DOI: 10.1016/j.chemphys.2012.09.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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12
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Hase M, Kitajima M. Interaction of coherent phonons with defects and elementary excitations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:073201. [PMID: 21386377 DOI: 10.1088/0953-8984/22/7/073201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We present an overview of the feasibility of using coherent phonon spectroscopy to study interaction dynamics of excited lattice vibrations with their environments. By exploiting the features of coherent phonons with a pump-probe technique, one can study lattice motions in a sub-picosecond time range. The dephasing properties tell us not only about interaction dynamics with carriers (electrons and holes) or thermal phonons but also about point defects in crystals. Modulations of the coherent phonon amplitude by more than two modes are closely related to phonon-carrier or phonon-phonon interferences. Related to this phenomenon, formation of coherent phonons at higher harmonics gives direct evidence for phonon-phonon couplings. A combined study of coherent phonons and ultrafast carrier response can be useful for understanding phonon-carrier interaction dynamics. For metals like zinc, nonequilibrium electrons may dominate the dynamics of both relaxation and generation of coherent phonons. The frequency chirp of coherent phonons can be a direct measure of how and when phonon-phonon and phonon-carrier couplings occur. Carbon nanotubes show some complicated behavior due to the existence of many modes with different symmetries, resulting in superposition or interference. To illustrate one of the most interesting applications, the selective excitation of specific phonon modes through the use of a pulse train technique is shown.
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Affiliation(s)
- Muneaki Hase
- Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8573, Japan.
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13
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Coherent Lattice Oscillations in Solids and Their Optical Control. SPRINGER SERIES IN CHEMICAL PHYSICS 2010. [DOI: 10.1007/978-3-642-03825-9_2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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14
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Carbone F, Baum P, Rudolf P, Zewail AH. Structural preablation dynamics of graphite observed by ultrafast electron crystallography. PHYSICAL REVIEW LETTERS 2008; 100:035501. [PMID: 18232996 DOI: 10.1103/physrevlett.100.035501] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Indexed: 05/06/2023]
Abstract
By means of time-resolved electron crystallography, we report direct observation of the structural dynamics of graphite, providing new insights into the processes involving coherent lattice motions and ultrafast graphene ablation. When graphite is excited by an ultrashort laser pulse, the excited carriers reach their equilibrium in less then one picosecond by transferring heat to a subset of strongly coupled optical phonons. The time-resolved diffraction data show that on such a time scale the crystal undergoes a contraction whose velocity depends on the excitation fluence. The contraction is followed by a large expansion which, at sufficiently high fluence, leads to the ablation of entire graphene layers, as recently predicted theoretically.
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Affiliation(s)
- Fabrizio Carbone
- Physical Biology Center for Ultrafast Science & Technology, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, CA 91125, USA
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15
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Misochko OV, Lebedev MV, Schäfer H, Dekorsy T. Coherent A(1) phonons in Te studied with tailored femtosecond pulses. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2007; 19:406220. [PMID: 22049119 DOI: 10.1088/0953-8984/19/40/406220] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We tailor the shape and phase of the pump-pulse spectrum in order to study coherent lattice dynamics in tellurium. Employing coherent control by splitting the pump pulse into a two-pulse sequence, we show that the oscillations due to A(1) coherent phonons can be cancelled but not enhanced as compared to single-pulse excitation of the same energy. We further demonstrate that a crucial factor for coherent phonon generation seems to be the bandwidth of the pulse spectrum. We observe that the coherent amplitude for long pump pulses decreases exponentially with pulse duration for both Gaussian and rectangular pulses. Finally, by varying the pulse chirp, we show that the coherent amplitude is independent of the chirp sign while the oscillation lifetime is slightly dependent on the chirp sign.
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Affiliation(s)
- O V Misochko
- Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka, Moscow region, Russia
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16
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Lee JD, Inoue J, Hase M. Ultrafast Fano resonance between optical phonons and electron-hole pairs at the onset of quasiparticle generation in a semiconductor. PHYSICAL REVIEW LETTERS 2006; 97:157405. [PMID: 17155359 DOI: 10.1103/physrevlett.97.157405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Indexed: 05/12/2023]
Abstract
Based on the many-body time-dependent approach applied to the ultrafast time region, we investigate the dynamics of creation of an optical phonon incorporating with the electron-hole continuum in a semiconductor. In the transient Fano resonance, due to an interference between those sharp (optical phonon) and continuum (electron-hole pair) quasiparticles, we find the robust destructive interference at birth of them, i.e., tau approximately 0 if the created phonon is coherent under the irradiation of ultrashort optical pulses. The origin is found to be the potential scattering of the electron-hole pair by the q=0 coherent phonon. This finding agrees well with the recent experiment.
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Affiliation(s)
- J D Lee
- International Center for Young Scientists, National Institute for Materials Science, Tsukuba 305-0044, Japan
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17
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Sun CK, Liang JC, Yu XY. Coherent acoustic phonon oscillations in semiconductor multiple quantum wells with piezoelectric fields. PHYSICAL REVIEW LETTERS 2000; 84:179-182. [PMID: 11015864 DOI: 10.1103/physrevlett.84.179] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/1999] [Indexed: 05/23/2023]
Abstract
Large coherent acoustic phonon oscillations were demonstrated using InGaN/GaN multiple quantum wells with piezoelectric fields. With UV femtosecond pulse excitation, photogenerated carriers screened the piezoelectric field and initiated the displacive coherent phonon oscillations. The specific phonon frequency was selected by the coupling between the periodic carrier distribution and the corresponding acoustic phonon mode. The induced acoustic phonon oscillation resulted in piezoelectric field modulation and then caused absorption variation through the quantum confined Franz-Keldysh effect. The wave vector uncertainty due to the finite sample width was found to determine the observed dephasing time.
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Affiliation(s)
- CK Sun
- Department of Electrical Engineering and Graduate Institute of Electro-Optical Engineering, Taipei 10617, Taiwan, Republic of China
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Garrett GA, Albrecht TF, Whitaker JF, Merlin R. Coherent THz Phonons Driven by Light Pulses and the Sb Problem: What is the Mechanism? PHYSICAL REVIEW LETTERS 1996; 77:3661-3664. [PMID: 10062276 DOI: 10.1103/physrevlett.77.3661] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Kuznetsov AV, Stanton CJ. Coherent phonon oscillations in GaAs. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:7555-7565. [PMID: 9977337 DOI: 10.1103/physrevb.51.7555] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Kuznetsov AV, Stanton CJ. Theory of coherent phonon oscillations in semiconductors. PHYSICAL REVIEW LETTERS 1994; 73:3243-3246. [PMID: 10057327 DOI: 10.1103/physrevlett.73.3243] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Yamamoto A, Mishina T, Masumoto Y, Nakayama M. Coherent oscillation of zone-folded phonon modes in GaAs-AlAs superlattices. PHYSICAL REVIEW LETTERS 1994; 73:740-743. [PMID: 10057525 DOI: 10.1103/physrevlett.73.740] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Mak G. Femtosecond transmission spectroscopy at the direct band edge of germanium. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:16817-16820. [PMID: 10010853 DOI: 10.1103/physrevb.49.16817] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Scholz R, Pfeifer T, Kurz H. Density-matrix theory of coherent phonon oscillations in germanium. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:16229-16236. [PMID: 10006045 DOI: 10.1103/physrevb.47.16229] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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