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Kurtz F, Dauwe TN, Yalunin SV, Storeck G, Horstmann JG, Böckmann H, Ropers C. Non-thermal phonon dynamics and a quenched exciton condensate probed by surface-sensitive electron diffraction. NATURE MATERIALS 2024; 23:890-897. [PMID: 38688990 PMCID: PMC11230895 DOI: 10.1038/s41563-024-01880-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 03/26/2024] [Indexed: 05/02/2024]
Abstract
Interactions among and between electrons and phonons steer the energy flow in photo-excited materials and govern the emergence of correlated phases. The strength of electron-phonon interactions, decay channels of strongly coupled modes and the evolution of three-dimensional order are revealed by electron or X-ray pulses tracking non-equilibrium structural dynamics. Despite such capabilities, the growing relevance of inherently anisotropic two-dimensional materials and functional heterostructures still calls for techniques with monolayer sensitivity and, specifically, access to out-of-plane phonon polarizations. Here, we resolve non-equilibrium phonon dynamics and quantify the excitonic contribution to the structural order parameter in 1T-TiSe2. To this end, we introduce ultrafast low-energy electron diffuse scattering and trace strongly momentum- and fluence-dependent phonon populations. Mediated by phonon-phonon scattering, a few-picosecond build-up near the zone boundary precedes a far slower generation of zone-centre acoustic modes. These weakly coupled phonons are shown to substantially delay overall equilibration in layered materials. Moreover, we record the surface structural response to a quench of the material's widely investigated exciton condensate, identifying an approximate 30:70 ratio of excitonic versus Peierls contributions to the total lattice distortion in the charge density wave phase. The surface-sensitive approach complements the ultrafast structural toolbox and may further elucidate the impact of phonon scattering in numerous other phenomena within two-dimensional materials, such as the formation of interlayer excitons in twisted bilayers.
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Affiliation(s)
- Felix Kurtz
- Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- 4th Physical Institute, Solids and Nanostructures, University of Göttingen, Göttingen, Germany
| | - Tim N Dauwe
- Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- 4th Physical Institute, Solids and Nanostructures, University of Göttingen, Göttingen, Germany
| | - Sergey V Yalunin
- Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- 4th Physical Institute, Solids and Nanostructures, University of Göttingen, Göttingen, Germany
| | - Gero Storeck
- Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- 4th Physical Institute, Solids and Nanostructures, University of Göttingen, Göttingen, Germany
| | - Jan Gerrit Horstmann
- Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Hannes Böckmann
- Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- 4th Physical Institute, Solids and Nanostructures, University of Göttingen, Göttingen, Germany
| | - Claus Ropers
- Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
- 4th Physical Institute, Solids and Nanostructures, University of Göttingen, Göttingen, Germany.
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2
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Huber M, Lin Y, Marini G, Moreschini L, Jozwiak C, Bostwick A, Calandra M, Lanzara A. Ultrafast creation of a light-induced semimetallic state in strongly excited 1T-TiSe 2. SCIENCE ADVANCES 2024; 10:eadl4481. [PMID: 38728393 PMCID: PMC11086600 DOI: 10.1126/sciadv.adl4481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 04/09/2024] [Indexed: 05/12/2024]
Abstract
Screening, a ubiquitous phenomenon associated with the shielding of electric fields by surrounding charges, has been widely adopted as a means to modify a material's properties. While most studies have relied on static changes of screening through doping or gating thus far, here we demonstrate that screening can also drive the onset of distinct quantum states on the ultrafast timescale. By using time- and angle-resolved photoemission spectroscopy, we show that intense optical excitation can drive 1T-TiSe2, a prototypical charge density wave material, almost instantly from a gapped into a semimetallic state. By systematically comparing changes in band structure over time and excitation strength with theoretical calculations, we find that the appearance of this state is likely caused by a dramatic reduction of the screening length. In summary, this work showcases how optical excitation enables the screening-driven design of a nonequilibrium semimetallic phase in TiSe2, possibly providing a general pathway into highly screened phases in other strongly correlated materials.
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Affiliation(s)
- Maximilian Huber
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yi Lin
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487, USA
| | - Giovanni Marini
- Graphene Labs, Fondazione Istituto Italiano di Tecnologia, I-16163 Genova, Italy
- Department of Physics, University of Trento, 38123 Povo, Italy
| | - Luca Moreschini
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Chris Jozwiak
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Aaron Bostwick
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Matteo Calandra
- Graphene Labs, Fondazione Istituto Italiano di Tecnologia, I-16163 Genova, Italy
- Department of Physics, University of Trento, 38123 Povo, Italy
- Sorbonne Universite, CNRS, Institut des Nanosciences de Paris, F-75252 Paris, France
| | - Alessandra Lanzara
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Physics Department, University of California, Berkeley, Berkeley, CA 94720, USA
- Kavli Energy NanoScience Institute, Berkeley, CA 94720, USA
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3
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Pouget JP, Canadell E. Structural approach to charge density waves in low-dimensional systems: electronic instability and chemical bonding. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:026501. [PMID: 38052072 DOI: 10.1088/1361-6633/ad124f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 12/05/2023] [Indexed: 12/07/2023]
Abstract
The charge density wave (CDW) instability, usually occurring in low-dimensional metals, has been a topic of interest for longtime. However, some very fundamental aspects of the mechanism remain unclear. Recently, a plethora of new CDW materials, a substantial fraction of which is two-dimensional or even three-dimensional, has been prepared and characterised as bulk and/or single-layers. As a result, the need for revisiting the primary mechanism of the instability, based on the electron-hole instability established more than 50 years ago for quasi-one-dimensional (quasi-1D) conductors, has clearly emerged. In this work, we consider a large number of CDW materials to revisit the main concepts used in understanding the CDW instability, and emphasise the key role of the momentum dependent electron-phonon coupling in linking electronic and structural degrees of freedom. We argue that for quasi-1D systems, earlier weak coupling theories work appropriately and the energy gain due to the CDW and the concomitant periodic lattice distortion (PLD) remains primarily due to a Fermi surface nesting mechanism. However, for materials with higher dimensionality, intermediate and strong coupling regimes are generally at work and the modification of the chemical bonding network by the PLD is at the heart of the instability. We emphasise the need for a microscopic approach blending condensed matter physics concepts and state-of-the-art first-principles calculations with quite fundamental chemical bonding ideas in understanding the CDW phenomenon in these materials.
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Affiliation(s)
- Jean-Paul Pouget
- Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Enric Canadell
- Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC, Campus de la UAB, 08193 Bellaterra, Spain, and Royal Academy of Sciences and Arts of Barcelona, Chemistry Section, La Rambla 115, 08002 Barcelona, Spain
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4
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Gutberlet T, Chang HT, Zayko S, Sivis M, Ropers C. High-sensitivity extreme-ultraviolet transient absorption spectroscopy enabled by machine learning. OPTICS EXPRESS 2023; 31:39757-39764. [PMID: 38041291 DOI: 10.1364/oe.495821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 09/19/2023] [Indexed: 12/03/2023]
Abstract
We present a novel denoising scheme for spectroscopy experiments employing broadband light sources and demonstrate its capabilities using transient absorption measurements with a high-harmonic source. Our scheme relies on measuring the probe spectra before and after interacting with the sample while capturing correlations between spectral components through machine learning approaches. With the present setup we achieve up to a tenfold improvement in noise suppression in XUV transient absorption spectra compared to the conventional pump on/ pump off referencing method. By utilizing strong spectral correlations in source fluctuations, the use of an artificial neural network facilitates pixel-wise noise reduction without requiring wavelength calibration of the reference spectrum. Our method can be adapted to a wide range of experiments and may be particularly advantageous for low repetition-rate systems, such as free electron lasers as well as laser-driven plasma and HHG sources. The enhanced sensitivity enables the investigation of subtle electron and lattice dynamics in the weak excitation regime, which is relevant for studying photovoltaics and photo-induced phase transitions in strongly correlated materials.
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Mori S, Tanimura H, Ichitsubo T, Sutou Y. Photoinduced Nonvolatile Displacive Transformation and Optical Switching in MnTe Semiconductors. ACS APPLIED MATERIALS & INTERFACES 2023; 15:42730-42736. [PMID: 37640668 DOI: 10.1021/acsami.3c07537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
MnTe is considered a promising candidate for next-generation phase change materials owing to the reversible and nonvolatile phase transformation between its α and β' phases by irradiation of a nanosecond laser or application of a pulse voltage. In this work, for a faster phase control of MnTe, the response of metastable β-MnTe thin films to femtosecond (fs) laser irradiation was investigated. Using ultrafast optical spectroscopy, we inferred transient phase transformation. Moreover, with an increase in laser-excitation fluence, a nonvolatile structural change from the β to α phase was experimentally observed by Raman spectroscopy and transmission electron microscopy without ablation damage on the sample. The observation results strongly suggest that the fs-laser-induced β → α phase transformation proceeds through the nucleation and growth mode without a large temperature increase.
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Affiliation(s)
- Shunsuke Mori
- Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11, Aoba-yama, Aoba-ku, Sendai 980-8579, Japan
| | - Hiroshi Tanimura
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Tetsu Ichitsubo
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Yuji Sutou
- Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11, Aoba-yama, Aoba-ku, Sendai 980-8579, Japan
- WPI-Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
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6
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Duan S, Xia W, Huang C, Wang S, Gu L, Liu H, Xiang D, Qian D, Guo Y, Zhang W. Ultrafast Switching from the Charge Density Wave Phase to a Metastable Metallic State in 1T-TiSe_{2}. PHYSICAL REVIEW LETTERS 2023; 130:226501. [PMID: 37327423 DOI: 10.1103/physrevlett.130.226501] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/28/2023] [Accepted: 05/04/2023] [Indexed: 06/18/2023]
Abstract
The ultrafast electronic structures of the charge density wave material 1T-TiSe_{2} were investigated by high-resolution time- and angle-resolved photoemission spectroscopy. We found that the quasiparticle populations drove ultrafast electronic phase transitions in 1T-TiSe_{2} within 100 fs after photoexcitation, and a metastable metallic state, which was significantly different from the equilibrium normal phase, was evidenced far below the charge density wave transition temperature. Detailed time- and pump-fluence-dependent experiments revealed that the photoinduced metastable metallic state was a result of the halted motion of the atoms through the coherent electron-phonon coupling process, and the lifetime of this state was prolonged to picoseconds with the highest pump fluence used in this study. Ultrafast electronic dynamics were well captured by the time-dependent Ginzburg-Landau model. Our work demonstrates a mechanism for realizing novel electronic states by photoinducing coherent motion of atoms in the lattice.
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Affiliation(s)
- Shaofeng Duan
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Wei Xia
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Chaozhi Huang
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shichong Wang
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Lingxiao Gu
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Haoran Liu
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Dao Xiang
- Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Dong Qian
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yanfeng Guo
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Wentao Zhang
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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7
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Huang Y, Lv S, Liu H, Cheng Q, Biao Y, Lu H, Lin X, Wang Z, Yang H, Chen H, Weng YX. Observation of photoinduced polarons in semimetal 1T-TiSe 2. NANOTECHNOLOGY 2023; 34:235707. [PMID: 36877995 DOI: 10.1088/1361-6528/acc188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 03/05/2023] [Indexed: 06/18/2023]
Abstract
In this work, ultrafast carrier dynamics of mechanically exfoliated 1T-TiSe2flakes from the high-quality single crystals with self-intercalated Ti atoms are investigated by femtosecond transient absorption spectroscopy. The observed coherent acoustic and optical phonon oscillations after ultrafast photoexcitation reveal the strong electron-phonon coupling in 1T-TiSe2. The ultrafast carrier dynamics probed in both visible and mid-infrared regions indicate that some photogenerated carriers localize near the intercalated Ti atoms and form small polarons rapidly within several picoseconds after photoexcitation due to the strong and short-range electron-phonon coupling. The formation of polarons leads to a reduction of carrier mobility and a long-time relaxation process of photoexcited carriers for several nanoseconds. The formation and dissociation rates of the photoinduced polarons are dependent on both the pump fluence and the thickness of TiSe2sample. This work offers new insights into the photogenerated carrier dynamics of 1T-TiSe2, and emphasizes the effects of intercalated atoms on the electron and lattice dynamics after photoexcitation.
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Affiliation(s)
- Yin Huang
- Beijing National Center for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Senhao Lv
- Beijing National Center for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Heyuan Liu
- Beijing National Center for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Qiuzhen Cheng
- Beijing National Center for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Yi Biao
- Beijing National Center for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Hongliang Lu
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Xiao Lin
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Zhuan Wang
- Beijing National Center for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Haitao Yang
- Beijing National Center for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, People's Republic of China
| | - Hailong Chen
- Beijing National Center for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, People's Republic of China
| | - Yu-Xiang Weng
- Beijing National Center for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, People's Republic of China
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8
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Lin Z, Wang C, Balassis A, Echeverry JP, Vasenko AS, Silkin VM, Chulkov EV, Shi Y, Zhang J, Guo J, Zhu X. Dramatic Plasmon Response to the Charge-Density-Wave Gap Development in 1T-TiSe_{2}. PHYSICAL REVIEW LETTERS 2022; 129:187601. [PMID: 36374677 DOI: 10.1103/physrevlett.129.187601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 04/20/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
1T-TiSe_{2} is one of the most studied charge density wave (CDW) systems, not only because of its peculiar properties related to the CDW transition, but also due to its status as a promising candidate of exciton insulator signaled by the proposed plasmon softening at the CDW wave vector. Using high-resolution electron energy loss spectroscopy, we report a systematic study of the temperature-dependent plasmon behaviors of 1T-TiSe_{2}. We unambiguously resolve the plasmon from phonon modes, revealing the existence of Landau damping to the plasmon at finite momentums, which does not support the plasmon softening picture for exciton condensation. Moreover, we discover that the plasmon lifetime at zero momentum responds dramatically to the band gap evolution associated with the CDW transition. The interband transitions near the Fermi energy in the normal phase are demonstrated to serve as a strong damping channel of plasmons, while such a channel in the CDW phase is suppressed due to the CDW gap opening, which results in the dramatic tunability of the plasmon in semimetals or small-gap semiconductors.
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Affiliation(s)
- Zijian Lin
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Cuixiang Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - A Balassis
- Department of Physics and Engineering Physics, Fordham University, 441 East Fordham Road, Bronx, New York 10458, USA
| | - J P Echeverry
- Universidad de Ibagué Carrera 22 Calle 67 B, Av. Ambalá Ibagué Tolima 730007, Colombia
| | - A S Vasenko
- HSE University, 101000 Moscow, Russia
- I. E. Tamm Department of Theoretical Physics, P. N. Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow, Russia
| | - V M Silkin
- Donostia International Physics Center (DIPC), 20018 San Sebastián/Donostia, Basque Country, Spain
- Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología, Facultad de Ciencias Químicas, Universidad del País Vasco UPV/EHU, Apartado 1072, 20080 San Sebastián/Donostia, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Basque Country, Spain
| | - E V Chulkov
- HSE University, 101000 Moscow, Russia
- Donostia International Physics Center (DIPC), 20018 San Sebastián/Donostia, Basque Country, Spain
- Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología, Facultad de Ciencias Químicas, Universidad del País Vasco UPV/EHU, Apartado 1072, 20080 San Sebastián/Donostia, Basque Country, Spain
| | - Youguo Shi
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Jiandi Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jiandong Guo
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Xuetao Zhu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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9
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Huber M, Lin Y, Dale N, Sailus R, Tongay S, Kaindl RA, Lanzara A. Revealing the order parameter dynamics of 1T-TiSe[Formula: see text] following optical excitation. Sci Rep 2022; 12:15860. [PMID: 36151110 PMCID: PMC9508156 DOI: 10.1038/s41598-022-19319-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 08/26/2022] [Indexed: 11/09/2022] Open
Abstract
The formation of a charge density wave state is characterized by an order parameter. The way it is established provides unique information on both the role that correlation plays in driving the charge density wave formation and the mechanism behind its formation. Here we use time and angle resolved photoelectron spectroscopy to optically perturb the charge-density phase in 1T-TiSe[Formula: see text] and follow the recovery of its order parameter as a function of energy, momentum and excitation density. Our results reveal that two distinct orders contribute to the gap formation, a CDW order and pseudogap-like order, manifested by an overall robustness to optical excitation. A detailed analysis of the magnitude of the the gap as a function of excitation density and delay time reveals the excitonic long-range nature of the CDW gap and the short-range Jahn-Teller character of the pseudogap order. In contrast to the gap, the intensity of the folded Se[Formula: see text]* band can only give access to the excitonic order. These results provide new information into the the long standing debate on the origin of the gap in TiSe[Formula: see text] and place it in the same context of other quantum materials where a pseudogap phase appears to be a precursor of long-range order.
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Affiliation(s)
- Maximilian Huber
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Yi Lin
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Nicholas Dale
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Physics Department, University of California Berkeley, Berkeley, CA 94720 USA
| | - Renee Sailus
- Materials Science and Engineering Department, Arizona State University, Phoenix, AZ 85281 USA
| | - Sefaattin Tongay
- Materials Science and Engineering Department, Arizona State University, Phoenix, AZ 85281 USA
| | - Robert A. Kaindl
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Department of Physics and CXFEL Labs, Arizona State University, Phoenix, AZ 85287 USA
| | - Alessandra Lanzara
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Physics Department, University of California Berkeley, Berkeley, CA 94720 USA
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10
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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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11
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Song Z, Huang J, Zhang S, Cao Y, Liu C, Zhang R, Zheng Q, Cao L, Huang L, Wang J, Qian T, Ding H, Zhou W, Zhang YY, Lu H, Shen C, Lin X, Du S, Gao HJ. Observation of an Incommensurate Charge Density Wave in Monolayer TiSe_{2}/CuSe/Cu(111) Heterostructure. PHYSICAL REVIEW LETTERS 2022; 128:026401. [PMID: 35089748 DOI: 10.1103/physrevlett.128.026401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 10/18/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
TiSe_{2} is a layered material exhibiting a commensurate (2×2×2) charge density wave (CDW) with a transition temperature of ∼200 K. Recently, incommensurate CDW in bulk TiSe_{2} draws great interest due to its close relationship with the emergence of superconductivity. Here, we report an incommensurate superstructure in monolayer TiSe_{2}/CuSe/Cu(111) heterostructure. Characterizations by low-energy electron diffraction and scanning tunneling microscopy show that the main wave vector of the superstructure is ∼0.41a^{*} or ∼0.59a^{*} (here a^{*} is in-plane reciprocal lattice constant of TiSe_{2}). After ruling out the possibility of moiré superlattices, according to the correlation of the wave vectors of the superstructure and the large indirect band gap below the Fermi level, we propose that the incommensurate superstructure is associated with an incommensurate charge density wave (I-CDW). It is noteworthy that the I-CDW is robust with a transition temperature over 600 K, much higher than that of commensurate CDW in pristine TiSe_{2}. Based on our data and analysis, we present that interface effect may play a key role in the formation of the I-CDW state.
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Affiliation(s)
- Zhipeng Song
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Jierui Huang
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Shuai Zhang
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Yun Cao
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Chen Liu
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Ruizi Zhang
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Qi Zheng
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Lu Cao
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Li Huang
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Jiaou Wang
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Tian Qian
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Hong Ding
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Wu Zhou
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Yu-Yang Zhang
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Hongliang Lu
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Chengmin Shen
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Xiao Lin
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Shixuan Du
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Hong-Jun Gao
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
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12
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Abstract
Advances over the past decade have presented new avenues to achieve control over material properties using intense pulses of electromagnetic radiation, with frequencies ranging from optical (approximately 1 PHz, or 1015 Hz) down to below 1 THz (1012 Hz). Some of these new developments have arisen from new experimental methods to drive and observe transient material properties, while others have emerged from new computational techniques that have made nonequilibrium dynamics more tractable to our understanding. One common issue with most attempts to realize control using electromagnetic pulses is the dissipation of energy, which in many cases poses a limit due to uncontrolled heating and has led to strong interest in using lower frequency and/or highly specific excitations to minimize this effect. Emergent developments in experimental tools using shaped X-ray pulses may in the future offer new possibilities for material control, provided that the issue of heat dissipation can be resolved for higher frequency light. The concept of using appropriately shaped pulses of light to control the properties of materials has a range of potential applications, and relies on an understanding of intricate couplings within the material.![]()
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Affiliation(s)
- Steven L Johnson
- Institute for Quantum Electronics, ETH Zürich, Auguste-Piccard-Hof 1, 8093 Zürich, Switzerland.
- SwissFEL, Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
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13
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Bie YQ, Zong A, Wang X, Jarillo-Herrero P, Gedik N. A versatile sample fabrication method for ultrafast electron diffraction. Ultramicroscopy 2021; 230:113389. [PMID: 34530284 DOI: 10.1016/j.ultramic.2021.113389] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 08/21/2021] [Accepted: 08/30/2021] [Indexed: 11/16/2022]
Abstract
Integral to the exploration of nonequilibrium phenomena in solid-state systems is the study of lattice motion after photoexcitation by a femtosecond laser pulse. For the past two decades, ultrafast electron diffraction (UED) has played a critical role in this regard. Despite remarkable progress in instrumental development, this technique is still bottlenecked by a demanding sample preparation process, where ultrathin single crystals of large lateral size are typically required. In this work, we describe an efficient, versatile method that yields high-quality, laterally extended (≥ 100 µm), and thin (≤ 50 nm) single crystals on amorphous films of Si3N4 windows. It applies to most exfoliable materials, including those reactive in ambient conditions, and promises clean, flat surfaces. Besides the natural extension to fabricating van der Waals heterostructures, our method can also be applied to future-generation UED that enables additional control of sample parameters, such as electrostatic gating and excitation by a locally enhanced terahertz field. Our work significantly expands the type of samples for UED studies and also finds application in other time-resolved techniques such as attosecond extreme-ultraviolet absorption spectroscopy. This method hence provides further opportunities to explore photoinduced transitions and to discover novel states of matter out of equilibrium.
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Affiliation(s)
- Ya-Qing Bie
- State Key Lab of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, 510275, China; Massachusetts Institute of Technology, Department of Physics, Cambridge, MA 02139, United States
| | - Alfred Zong
- Massachusetts Institute of Technology, Department of Physics, Cambridge, MA 02139, United States; University of California at Berkeley, Department of Chemistry, Berkeley, CA 94720, United States
| | - Xirui Wang
- Massachusetts Institute of Technology, Department of Physics, Cambridge, MA 02139, United States
| | - Pablo Jarillo-Herrero
- Massachusetts Institute of Technology, Department of Physics, Cambridge, MA 02139, United States
| | - Nuh Gedik
- Massachusetts Institute of Technology, Department of Physics, Cambridge, MA 02139, United States.
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14
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Duan S, Cheng Y, Xia W, Yang Y, Xu C, Qi F, Huang C, Tang T, Guo Y, Luo W, Qian D, Xiang D, Zhang J, Zhang W. Optical manipulation of electronic dimensionality in a quantum material. Nature 2021; 595:239-244. [PMID: 34234338 DOI: 10.1038/s41586-021-03643-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 05/13/2021] [Indexed: 02/06/2023]
Abstract
Exotic phenomena can be achieved in quantum materials by confining electronic states into two dimensions. For example, relativistic fermions are realized in a single layer of carbon atoms1, the quantized Hall effect can result from two-dimensional (2D) systems2,3, and the superconducting transition temperature can be considerably increased in a one-atomic-layer material4,5. Ordinarily, a 2D electronic system can be obtained by exfoliating the layered materials, growing monolayer materials on substrates, or establishing interfaces between different materials. Here we use femtosecond infrared laser pulses to invert the periodic lattice distortion sectionally in a three-dimensional (3D) charge density wave material (1T-TiSe2), creating macroscopic domain walls of transient 2D ordered electronic states with unusual properties. The corresponding ultrafast electronic and lattice dynamics are captured by time-resolved and angle-resolved photoemission spectroscopy6 and ultrafast electron diffraction at energies of the order of megaelectronvolts7. Moreover, in the photoinduced 2D domain wall near the surface we identify a phase with enhanced density of states and signatures of potential opening of an energy gap near the Fermi energy. Such optical modulation of atomic motion is an alternative path towards realizing 2D electronic states and will be a useful platform upon which novel phases in quantum materials may be discovered.
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Affiliation(s)
- Shaofeng Duan
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - Yun Cheng
- Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - Wei Xia
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yuanyuan Yang
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - Chengyang Xu
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - Fengfeng Qi
- Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - Chaozhi Huang
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - Tianwei Tang
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - Yanfeng Guo
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
| | - Weidong Luo
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China.,Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai, China
| | - Dong Qian
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China.,Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, China
| | - Dao Xiang
- Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China. .,Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, China. .,Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University, Shanghai, China.
| | - Jie Zhang
- Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - Wentao Zhang
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China.
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15
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Maklar J, Windsor YW, Nicholson CW, Puppin M, Walmsley P, Esposito V, Porer M, Rittmann J, Leuenberger D, Kubli M, Savoini M, Abreu E, Johnson SL, Beaud P, Ingold G, Staub U, Fisher IR, Ernstorfer R, Wolf M, Rettig L. Nonequilibrium charge-density-wave order beyond the thermal limit. Nat Commun 2021; 12:2499. [PMID: 33941788 PMCID: PMC8093280 DOI: 10.1038/s41467-021-22778-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 03/26/2021] [Indexed: 12/02/2022] Open
Abstract
The interaction of many-body systems with intense light pulses may lead to novel emergent phenomena far from equilibrium. Recent discoveries, such as the optical enhancement of the critical temperature in certain superconductors and the photo-stabilization of hidden phases, have turned this field into an important research frontier. Here, we demonstrate nonthermal charge-density-wave (CDW) order at electronic temperatures far greater than the thermodynamic transition temperature. Using time- and angle-resolved photoemission spectroscopy and time-resolved X-ray diffraction, we investigate the electronic and structural order parameters of an ultrafast photoinduced CDW-to-metal transition. Tracking the dynamical CDW recovery as a function of electronic temperature reveals a behaviour markedly different from equilibrium, which we attribute to the suppression of lattice fluctuations in the transient nonthermal phonon distribution. A complete description of the system's coherent and incoherent order-parameter dynamics is given by a time-dependent Ginzburg-Landau framework, providing access to the transient potential energy surfaces.
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Affiliation(s)
- J Maklar
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany.
| | - Y W Windsor
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
| | - C W Nicholson
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
- Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Fribourg, Switzerland
| | - M Puppin
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
- Laboratory of Ultrafast Spectroscopy, ISIC, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - P Walmsley
- Geballe Laboratory for Advanced Materials and Department of Applied Physics, Stanford University, Stanford, CA, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - V Esposito
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - M Porer
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - J Rittmann
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - D Leuenberger
- Department of Physics, University of Zürich, Zürich, Switzerland
| | - M Kubli
- Institute for Quantum Electronics, Physics Department, ETH Zürich, Zürich, Switzerland
| | - M Savoini
- Institute for Quantum Electronics, Physics Department, ETH Zürich, Zürich, Switzerland
| | - E Abreu
- Institute for Quantum Electronics, Physics Department, ETH Zürich, Zürich, Switzerland
| | - S L Johnson
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
- Institute for Quantum Electronics, Physics Department, ETH Zürich, Zürich, Switzerland
| | - P Beaud
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - G Ingold
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - U Staub
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - I R Fisher
- Geballe Laboratory for Advanced Materials and Department of Applied Physics, Stanford University, Stanford, CA, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - R Ernstorfer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
| | - M Wolf
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
| | - L Rettig
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany.
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16
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Lu H, Gauthier A, Hepting M, Tremsin AS, Reid AH, Kirchmann PS, Shen ZX, Devereaux TP, Shao YC, Feng X, Coslovich G, Hussain Z, Dakovski GL, Chuang YD, Lee WS. Time-resolved RIXS experiment with pulse-by-pulse parallel readout data collection using X-ray free electron laser. Sci Rep 2020; 10:22226. [PMID: 33335197 PMCID: PMC7746750 DOI: 10.1038/s41598-020-79210-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 11/30/2020] [Indexed: 11/21/2022] Open
Abstract
Time-resolved resonant inelastic X-ray scattering (RIXS) is one of the developing techniques enabled by the advent of X-ray free electron laser (FEL). It is important to evaluate how the FEL jitter, which is inherent in the self-amplified spontaneous emission process, influences the RIXS measurement. Here, we use a microchannel plate (MCP) based Timepix soft X-ray detector to conduct a time-resolved RIXS measurement at the Ti L3-edge on a charge-density-wave material TiSe2. The fast parallel Timepix readout and single photon sensitivity enable pulse-by-pulse data acquisition and analysis. Due to the FEL jitter, low detection efficiency of spectrometer, and low quantum yield of RIXS process, we find that less than 2% of the X-ray FEL pulses produce signals, preventing acquiring sufficient data statistics while maintaining temporal and energy resolution in this measurement. These limitations can be mitigated by using future X-ray FELs with high repetition rates, approaching MHz such as the European XFEL in Germany and LCLS-II in the USA, as well as by utilizing advanced detectors, such as the prototype used in this study.
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Affiliation(s)
- H Lu
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - A Gauthier
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - M Hepting
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - A S Tremsin
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, 94720, USA
| | - A H Reid
- Linac Coherent Light Source (LCLS), SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - P S Kirchmann
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.,Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA, 94305, USA
| | - Z X Shen
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.,Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA, 94305, USA
| | - T P Devereaux
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.,Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA, 94305, USA.,Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Y C Shao
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - X Feng
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - G Coslovich
- Linac Coherent Light Source (LCLS), SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Z Hussain
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - G L Dakovski
- Linac Coherent Light Source (LCLS), SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Y D Chuang
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - W S Lee
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.
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17
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Hu Q, Xu S, Guo X, Liu H, Chen Z, Wang B, Ang R. Superconductivity related to the suppression of exciton formation in 1T-TiSe 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:425602. [PMID: 32720648 DOI: 10.1088/1361-648x/aba1ab] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/01/2020] [Indexed: 06/11/2023]
Abstract
In strongly correlated electron system, the impact of elementary substitution or intercalation plays a crucial role in determining electronic ground state among various macroscopic quantum phases such as charge order and superconductivity. Here, we report that simultaneous Cu intercalation and Ta substitution at Ti site in 1T-CuxTi0.8Ta0.2Se2induce an intrinsic electronic phase diagram, characterized by an inherent superconducting transition in thexregion of 0 ⩽x⩽ 0.12, with a maximum superconducting transition temperatureTcof 2.5 K forx= 0.04, in contrast to the non-superconducting sample 1T-Cu0.04TiSe2. The increased density of free charge carriers screen the Coulomb interaction between electron-hole pairs effectively, promoting the occurrence of superconductivity favourably. Present results suggest that the Cu intercalation and the Ta substitution-induced suppression of the exciton condensation boost the superconductivity, shedding new light on the fundamental physics of the interplay between superconductivity, charge order, and electron correlation.
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Affiliation(s)
- Qing Hu
- Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, People's Republic of China
| | - Shuxiang Xu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Xuming Guo
- Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, People's Republic of China
| | - Hangtian Liu
- Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, People's Republic of China
| | - Zhiyu Chen
- Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, People's Republic of China
| | - Bosen Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
| | - Ran Ang
- Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, People's Republic of China
- Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610065, People's Republic of China
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18
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You P, Chen D, Lian C, Zhang C, Meng S. First‐principles dynamics of photoexcited molecules and materials towards a quantum description. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2020. [DOI: 10.1002/wcms.1492] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Peiwei You
- 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
| | - Daqiang Chen
- 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
| | - Chao Lian
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing China
| | - Cui Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing China
- Songshan Lake Materials Laboratory Dongguan China
| | - Sheng Meng
- 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 China
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19
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Nakamura A, Shimojima T, Chiashi Y, Kamitani M, Sakai H, Ishiwata S, Li H, Ishizaka K. Nanoscale Imaging of Unusual Photoacoustic Waves in Thin Flake VTe 2. NANO LETTERS 2020; 20:4932-4938. [PMID: 32463678 DOI: 10.1021/acs.nanolett.0c01006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The control of acoustic phonons, which are the carriers of sound and heat, has become the focus of increasing attention because of a demand for manipulating the sonic and thermal properties of nanometric devices. In particular, the photoacoustic effect using ultrafast optical pulses has a promising potential for the optical manipulation of phonons in the picosecond time regime. So far, its mechanism has been mostly based on the commonplace thermoelastic expansion in isotropic media, which has limited applicability. In this study, we investigate a conceptually new mechanism of the photoacoustic effect involving a structural instability that utilizes a transition-metal dichalcogenide VTe2 with a ribbon-type charge-density-wave (CDW). Ultrafast electron microscope imaging and diffraction measurements reveal the generation and propagation of unusual acoustic waves in a nanometric thin plate associated with optically induced instantaneous CDW dissolution. Our results highlight the capability of photoinduced structural instabilities as a source of coherent acoustic waves.
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Affiliation(s)
- Asuka Nakamura
- RIKEN Center for Emergent Matter Science, Wako, Saitama 351-0198, Japan
| | | | - Yusuke Chiashi
- Quantum-Phase Electronics Center and Department of Applied Physics, The University of Tokyo, Hongo, Tokyo 113-8656, Japan
| | - Manabu Kamitani
- RIKEN Center for Emergent Matter Science, Wako, Saitama 351-0198, Japan
| | - Hideaki Sakai
- Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Shintaro Ishiwata
- Quantum-Phase Electronics Center and Department of Applied Physics, The University of Tokyo, Hongo, Tokyo 113-8656, Japan
- Division of Materials Physics, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Han Li
- Quantum-Phase Electronics Center and Department of Applied Physics, The University of Tokyo, Hongo, Tokyo 113-8656, Japan
| | - Kyoko Ishizaka
- RIKEN Center for Emergent Matter Science, Wako, Saitama 351-0198, Japan
- Quantum-Phase Electronics Center and Department of Applied Physics, The University of Tokyo, Hongo, Tokyo 113-8656, Japan
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20
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Lian C, Zhang SJ, Hu SQ, Guan MX, Meng S. Ultrafast charge ordering by self-amplified exciton-phonon dynamics in TiSe 2. Nat Commun 2020; 11:43. [PMID: 31896745 PMCID: PMC6940384 DOI: 10.1038/s41467-019-13672-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 11/14/2019] [Indexed: 11/24/2022] Open
Abstract
The origin of charge density waves (CDWs) in TiSe\documentclass[12pt]{minimal}
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\begin{document}$${}_{2}$$\end{document}2 has long been debated, mainly due to the difficulties in identifying the timescales of the excitonic pairing and electron–phonon coupling (EPC). Without a time-resolved and microscopic mechanism, one has to assume simultaneous appearance of CDW and periodic lattice distortions (PLD). Here, we accomplish a complete separation of ultrafast exciton and PLD dynamics and unravel their interplay in our real-time time-dependent density functional theory simulations. We find that laser pulses knock off the exciton order and induce a homogeneous bonding–antibonding transition in the initial 20 fs, then the weakened electronic order triggers ionic movements antiparallel to the original PLD. The EPC comes into play after the initial 20 fs, and the two processes mutually amplify each other leading to a complete inversion of CDW ordering. The self-amplified dynamics reproduces the evolution of band structures in agreement with photoemission experiments. Hence we resolve the key processes in the initial dynamics of CDWs that help elucidate the underlying mechanism. The physical origins of charge density waves in 1T-TiSe2 and their response to ultrafast excitation have long been a topic of theoretical and experimental debate. Here the authors present an ab initio theory that successfully captures the observed dynamics of charge density wave formation.
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Affiliation(s)
- Chao Lian
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Sheng-Jie Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Shi-Qi Hu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Meng-Xue Guan
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Sheng Meng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China. .,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, P. R. China. .,Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, P. R. China.
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21
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Zong A, Shen X, Kogar A, Ye L, Marks C, Chowdhury D, Rohwer T, Freelon B, Weathersby S, Li R, Yang J, Checkelsky J, Wang X, Gedik N. Ultrafast manipulation of mirror domain walls in a charge density wave. SCIENCE ADVANCES 2018; 4:eaau5501. [PMID: 30345365 PMCID: PMC6195337 DOI: 10.1126/sciadv.aau5501] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 09/07/2018] [Indexed: 05/02/2023]
Abstract
Domain walls (DWs) are singularities in an ordered medium that often host exotic phenomena such as charge ordering, insulator-metal transition, or superconductivity. The ability to locally write and erase DWs is highly desirable, as it allows one to design material functionality by patterning DWs in specific configurations. We demonstrate such capability at room temperature in a charge density wave (CDW), a macroscopic condensate of electrons and phonons, in ultrathin 1T-TaS2. A single femtosecond light pulse is shown to locally inject or remove mirror DWs in the CDW condensate, with probabilities tunable by pulse energy and temperature. Using time-resolved electron diffraction, we are able to simultaneously track anti-synchronized CDW amplitude oscillations from both the lattice and the condensate, where photoinjected DWs lead to a red-shifted frequency. Our demonstration of reversible DW manipulation may pave new ways for engineering correlated material systems with light.
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Affiliation(s)
- Alfred Zong
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Xiaozhe Shen
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Anshul Kogar
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Linda Ye
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Carolyn Marks
- Center for Nanoscale Systems, Harvard University, Cambridge, MA 02138, USA
| | - Debanjan Chowdhury
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Timm Rohwer
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Byron Freelon
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Renkai Li
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Jie Yang
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Joseph Checkelsky
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Xijie Wang
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Nuh Gedik
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Corresponding author.
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22
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Porer M, Fechner M, Bothschafter EM, Rettig L, Savoini M, Esposito V, Rittmann J, Kubli M, Neugebauer MJ, Abreu E, Kubacka T, Huber T, Lantz G, Parchenko S, Grübel S, Paarmann A, Noack J, Beaud P, Ingold G, Aschauer U, Johnson SL, Staub U. Ultrafast Relaxation Dynamics of the Antiferrodistortive Phase in Ca Doped SrTiO_{3}. PHYSICAL REVIEW LETTERS 2018; 121:055701. [PMID: 30118273 DOI: 10.1103/physrevlett.121.055701] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Indexed: 06/08/2023]
Abstract
The ultrafast dynamics of the octahedral rotation in Ca:SrTiO_{3} is studied by time-resolved x-ray diffraction after photoexcitation over the band gap. By monitoring the diffraction intensity of a superlattice reflection that is directly related to the structural order parameter of the soft-mode driven antiferrodistortive phase in Ca:SrTiO_{3}, we observe an ultrafast relaxation on a 0.2 ps timescale of the rotation of the oxygen octahedron, which is found to be independent of the initial temperature despite large changes in the corresponding soft-mode frequency. A further, much smaller reduction on a slower picosecond timescale is attributed to thermal effects. Time-dependent density-functional-theory calculations show that the fast response can be ascribed to an ultrafast displacive modification of the soft-mode potential towards the normal state induced by holes created in the oxygen 2p states.
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Affiliation(s)
- M Porer
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - M Fechner
- Max Planck Institute for the Structure and Dynamics of Matter, CFEL, 22761 Hamburg, Germany
- Materials Theory, ETH Zürich, 8093 Zürich, Switzerland
| | - E M Bothschafter
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - L Rettig
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, 14195 Berlin, Germany
| | - M Savoini
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - V Esposito
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - J Rittmann
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - M Kubli
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - M J Neugebauer
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - E Abreu
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - T Kubacka
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - T Huber
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - G Lantz
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - S Parchenko
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - S Grübel
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - A Paarmann
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, 14195 Berlin, Germany
| | - J Noack
- Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society, 14195 Berlin, Germany
| | - P Beaud
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - G Ingold
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - U Aschauer
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - S L Johnson
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - U Staub
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
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23
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Johnson SL, Savoini M, Beaud P, Ingold G, Staub U, Carbone F, Castiglioni L, Hengsberger M, Osterwalder J. Watching ultrafast responses of structure and magnetism in condensed matter with momentum-resolved probes. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2017; 4:061506. [PMID: 29308418 PMCID: PMC5741437 DOI: 10.1063/1.4996176] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 09/21/2017] [Indexed: 05/26/2023]
Abstract
We present a non-comprehensive review of some representative experimental studies in crystalline condensed matter systems where the effects of intense ultrashort light pulses are probed using x-ray diffraction and photoelectron spectroscopy. On an ultrafast (sub-picosecond) time scale, conventional concepts derived from the assumption of thermodynamic equilibrium must often be modified in order to adequately describe the time-dependent changes in material properties. There are several commonly adopted approaches to this modification, appropriate in different experimental circumstances. One approach is to treat the material as a collection of quasi-thermal subsystems in thermal contact with each other in the so-called "N-temperature" models. On the other extreme, one can also treat the time-dependent changes as fully coherent dynamics of a sometimes complex network of excitations. Here, we present examples of experiments that fall into each of these categories, as well as experiments that partake of both models. We conclude with a discussion of the limitations and future potential of these concepts.
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Affiliation(s)
- S L Johnson
- Institute for Quantum Electronics, Eidgenössische Technische Hochschule (ETH) Zürich, CH-8093 Zurich, Switzerland
| | - M Savoini
- Institute for Quantum Electronics, Eidgenössische Technische Hochschule (ETH) Zürich, CH-8093 Zurich, Switzerland
| | - P Beaud
- Paul Scherrer Institut, CH-5032 Villigen, Switzerland
| | - G Ingold
- Paul Scherrer Institut, CH-5032 Villigen, Switzerland
| | - U Staub
- Paul Scherrer Institut, CH-5032 Villigen, Switzerland
| | - F Carbone
- Laboratory for Ultrafast Microscopy and Electron Scattering, ICMP, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - L Castiglioni
- Department of Physics, University of Zurich, CH-8057 Zurich, Switzerland
| | - M Hengsberger
- Department of Physics, University of Zurich, CH-8057 Zurich, Switzerland
| | - J Osterwalder
- Department of Physics, University of Zurich, CH-8057 Zurich, Switzerland
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24
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Abela R, Beaud P, van Bokhoven JA, Chergui M, Feurer T, Haase J, Ingold G, Johnson SL, Knopp G, Lemke H, Milne CJ, Pedrini B, Radi P, Schertler G, Standfuss J, Staub U, Patthey L. Perspective: Opportunities for ultrafast science at SwissFEL. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2017; 4:061602. [PMID: 29376109 PMCID: PMC5758366 DOI: 10.1063/1.4997222] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 10/17/2017] [Indexed: 05/03/2023]
Abstract
We present the main specifications of the newly constructed Swiss Free Electron Laser, SwissFEL, and explore its potential impact on ultrafast science. In light of recent achievements at current X-ray free electron lasers, we discuss the potential territory for new scientific breakthroughs offered by SwissFEL in Chemistry, Biology, and Materials Science, as well as nonlinear X-ray science.
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Affiliation(s)
- Rafael Abela
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Paul Beaud
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Jeroen A van Bokhoven
- Laboratory for Catalysis and Sustainable Chemistry, Paul-Scherrer Institute, 5232 Villigen PSI, and Department of Chemistry, ETH-Zürich, 8093 Zürich, Switzerland
| | - Majed Chergui
- Laboratoire de Spectroscopie Ultrarapide (LSU) and Lausanne Centre for Ultrafast Science (LACUS), Ecole Polytechnique Fédérale de Lausanne (EPFL), ISIC-FSB, Station 6, 1015 Lausanne, Switzerland
| | - Thomas Feurer
- Institute of Applied Physics, University of Bern, Bern, Switzerland
| | - Johannes Haase
- Laboratory for Catalysis and Sustainable Chemistry, Paul-Scherrer Institute, 5232 Villigen PSI, and Department of Chemistry, ETH-Zürich, 8093 Zürich, Switzerland
| | - Gerhard Ingold
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Steven L Johnson
- Institute for Quantum Electronics, Eidgenössische Technische Hochschule (ETH) Zürich, 8093 Zurich, Switzerland
| | - Gregor Knopp
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Henrik Lemke
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Chris J Milne
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Bill Pedrini
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Peter Radi
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | | | - Jörg Standfuss
- Division of Biology and Chemistry, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Urs Staub
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Luc Patthey
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
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25
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Wei L, Sun S, Guo C, Li Z, Sun K, Liu Y, Lu W, Sun Y, Tian H, Yang H, Li J. Dynamic diffraction effects and coherent breathing oscillations in ultrafast electron diffraction in layered 1 T-TaSeTe. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2017; 4:044012. [PMID: 28470025 PMCID: PMC5404908 DOI: 10.1063/1.4979643] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 03/21/2017] [Indexed: 05/06/2023]
Abstract
Anisotropic lattice movements due to the difference between intralayer and interlayer bonding are observed in the layered transition-metal dichalcogenide 1T-TaSeTe following femtosecond laser pulse excitation. Our ultrafast electron diffraction investigations using 4D-transmission electron microscopy (4D-TEM) clearly reveal that the intensity of Bragg reflection spots often changes remarkably due to the dynamic diffraction effects and anisotropic lattice movement. Importantly, the temporal diffracted intensity from a specific crystallographic plane depends on the deviation parameter s, which is commonly used in the theoretical study of diffraction intensity. Herein, we report on lattice thermalization and structural oscillations in layered 1T-TaSeTe, analyzed by dynamic diffraction theory. Ultrafast alterations of satellite spots arising from the charge density wave in the present system are also briefly discussed.
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Affiliation(s)
| | - Shuaishuai Sun
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Cong Guo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | | | | | - Yu Liu
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - Wenjian Lu
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China
| | | | - Huanfang Tian
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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26
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Laulhé C, Huber T, Lantz G, Ferrer A, Mariager SO, Grübel S, Rittmann J, Johnson JA, Esposito V, Lübcke A, Huber L, Kubli M, Savoini M, Jacques VLR, Cario L, Corraze B, Janod E, Ingold G, Beaud P, Johnson SL, Ravy S. Ultrafast Formation of a Charge Density Wave State in 1T-TaS_{2}: Observation at Nanometer Scales Using Time-Resolved X-Ray Diffraction. PHYSICAL REVIEW LETTERS 2017; 118:247401. [PMID: 28665649 DOI: 10.1103/physrevlett.118.247401] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Indexed: 05/19/2023]
Abstract
Femtosecond time-resolved x-ray diffraction is used to study a photoinduced phase transition between two charge density wave (CDW) states in 1T-TaS_{2}, namely the nearly commensurate (NC) and the incommensurate (I) CDW states. Structural modulations associated with the NC-CDW order are found to disappear within 400 fs. The photoinduced I-CDW phase then develops through a nucleation and growth process which ends 100 ps after laser excitation. We demonstrate that the newly formed I-CDW phase is fragmented into several nanometric domains that are growing through a coarsening process. The coarsening dynamics is found to follow the universal Lifshitz-Allen-Cahn growth law, which describes the ordering kinetics in systems exhibiting a nonconservative order parameter.
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Affiliation(s)
- C Laulhé
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin-BP 48, F-91192 Gif-sur-Yvette, France
- Université Paris-Saclay (Université Paris-Sud), F-91405 Orsay Cedex, France
| | - T Huber
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - G Lantz
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS, UMR 8502, F-91405 Orsay, France
| | - A Ferrer
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - S O Mariager
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - S Grübel
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - J Rittmann
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - J A Johnson
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - V Esposito
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - A Lübcke
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - L Huber
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - M Kubli
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - M Savoini
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - V L R Jacques
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS, UMR 8502, F-91405 Orsay, France
| | - L Cario
- Institut des Matériaux Jean Rouxel-UMR 6502, Université de Nantes, 2 rue de la Houssinière, F-44322 Nantes, France
| | - B Corraze
- Institut des Matériaux Jean Rouxel-UMR 6502, Université de Nantes, 2 rue de la Houssinière, F-44322 Nantes, France
| | - E Janod
- Institut des Matériaux Jean Rouxel-UMR 6502, Université de Nantes, 2 rue de la Houssinière, F-44322 Nantes, France
| | - G Ingold
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - P Beaud
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - S L Johnson
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - S Ravy
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS, UMR 8502, F-91405 Orsay, France
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27
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Mathias S, Eich S, Urbancic J, Michael S, Carr AV, Emmerich S, Stange A, Popmintchev T, Rohwer T, Wiesenmayer M, Ruffing A, Jakobs S, Hellmann S, Matyba P, Chen C, Kipp L, Bauer M, Kapteyn HC, Schneider HC, Rossnagel K, Murnane MM, Aeschlimann M. Self-amplified photo-induced gap quenching in a correlated electron material. Nat Commun 2016; 7:12902. [PMID: 27698341 PMCID: PMC5059442 DOI: 10.1038/ncomms12902] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 08/09/2016] [Indexed: 11/10/2022] Open
Abstract
Capturing the dynamic electronic band structure of a correlated material presents a powerful capability for uncovering the complex couplings between the electronic and structural degrees of freedom. When combined with ultrafast laser excitation, new phases of matter can result, since far-from-equilibrium excited states are instantaneously populated. Here, we elucidate a general relation between ultrafast non-equilibrium electron dynamics and the size of the characteristic energy gap in a correlated electron material. We show that carrier multiplication via impact ionization can be one of the most important processes in a gapped material, and that the speed of carrier multiplication critically depends on the size of the energy gap. In the case of the charge-density wave material 1T-TiSe2, our data indicate that carrier multiplication and gap dynamics mutually amplify each other, which explains-on a microscopic level-the extremely fast response of this material to ultrafast optical excitation.
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Affiliation(s)
- S Mathias
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - S Eich
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - J Urbancic
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - S Michael
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - A V Carr
- JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
| | - S Emmerich
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - A Stange
- Institute of Experimental and Applied Physics, University of Kiel, 24098 Kiel, Germany
| | - T Popmintchev
- JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
| | - T Rohwer
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.,Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - M Wiesenmayer
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - A Ruffing
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - S Jakobs
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - S Hellmann
- Institute of Experimental and Applied Physics, University of Kiel, 24098 Kiel, Germany
| | - P Matyba
- JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
| | - C Chen
- JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
| | - L Kipp
- Institute of Experimental and Applied Physics, University of Kiel, 24098 Kiel, Germany
| | - M Bauer
- Institute of Experimental and Applied Physics, University of Kiel, 24098 Kiel, Germany
| | - H C Kapteyn
- JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
| | - H C Schneider
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - K Rossnagel
- Institute of Experimental and Applied Physics, University of Kiel, 24098 Kiel, Germany
| | - M M Murnane
- JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
| | - M Aeschlimann
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
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28
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Danz T, Liu Q, Zhu XD, Wang LH, Cheong SW, Radu I, Ropers C, Tobey RI. Structural and magnetic characterization of large area, free-standing thin films of magnetic ion intercalated dichalcogenides Mn0.25TaS2 and Fe0.25TaS2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:356002. [PMID: 27382929 DOI: 10.1088/0953-8984/28/35/356002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Free-standing thin films of magnetic ion intercalated transition metal dichalcogenides are produced using ultramicrotoming techniques. Films of thicknesses ranging from 30 nm to 250 nm were achieved and characterized using transmission electron diffraction and x-ray magnetic circular dichroism. Diffraction measurements visualize the long range crystallographic ordering of the intercalated ions, while the dichroism measurements directly assess the orbital contributions to the total magnetic moment. We thus verify the unquenched orbital moment in Fe0.25TaS2 and measure the fully quenched orbital contribution in Mn0.25TaS2. Such films can be used in a wide variety of ultrafast x-ray and electron techniques that benefit from transmission geometries, and allow measurements of ultrafast structural, electronic, and magnetization dynamics in space and time.
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Affiliation(s)
- Th Danz
- 4th Physical Institute-Solids and Nanostructures, University of Göttingen, 37077 Göttingen, Germany
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29
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Manz S, Casandruc A, Zhang D, Zhong Y, Loch RA, Marx A, Hasegawa T, Liu LC, Bayesteh S, Delsim-Hashemi H, Hoffmann M, Felber M, Hachmann M, Mayet F, Hirscht J, Keskin S, Hada M, Epp SW, Flöttmann K, Miller RJD. Mapping atomic motions with ultrabright electrons: towards fundamental limits in space-time resolution. Faraday Discuss 2015; 177:467-91. [PMID: 25631530 DOI: 10.1039/c4fd00204k] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The long held objective of directly observing atomic motions during the defining moments of chemistry has been achieved based on ultrabright electron sources that have given rise to a new field of atomically resolved structural dynamics. This class of experiments requires not only simultaneous sub-atomic spatial resolution with temporal resolution on the 100 femtosecond time scale but also has brightness requirements approaching single shot atomic resolution conditions. The brightness condition is in recognition that chemistry leads generally to irreversible changes in structure during the experimental conditions and that the nanoscale thin samples needed for electron structural probes pose upper limits to the available sample or "film" for atomic movies. Even in the case of reversible systems, the degree of excitation and thermal effects require the brightest sources possible for a given space-time resolution to observe the structural changes above background. Further progress in the field, particularly to the study of biological systems and solution reaction chemistry, requires increased brightness and spatial coherence, as well as an ability to tune the electron scattering cross-section to meet sample constraints. The electron bunch density or intensity depends directly on the magnitude of the extraction field for photoemitted electron sources and electron energy distribution in the transverse and longitudinal planes of electron propagation. This work examines the fundamental limits to optimizing these parameters based on relativistic electron sources using re-bunching cavity concepts that are now capable of achieving 10 femtosecond time scale resolution to capture the fastest nuclear motions. This analysis is given for both diffraction and real space imaging of structural dynamics in which there are several orders of magnitude higher space-time resolution with diffraction methods. The first experimental results from the Relativistic Electron Gun for Atomic Exploration (REGAE) are given that show the significantly reduced multiple electron scattering problem in this regime, which opens up micron scale systems, notably solution phase chemistry, to atomically resolved structural dynamics.
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Affiliation(s)
- Stephanie Manz
- The Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Luruper Chaussee 149, Hamburg 22761, Germany.
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Wingert J, Singer A, Shpyrko OG. A new method for studying sub-pulse dynamics at synchrotron sources. JOURNAL OF SYNCHROTRON RADIATION 2015; 22:1141-1146. [PMID: 26289263 DOI: 10.1107/s1600577515013806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 07/21/2015] [Indexed: 06/04/2023]
Abstract
The possibility of studying dynamics at time scales on the order of the pulse duration at synchrotron X-ray sources with present avalanche photodiode point detection technology is investigated, without adopting pump-probe techniques. It is found that sample dynamics can be characterized by counting single and double photon events and an analytical approach is developed to estimate the time required for a statistically significant measurement to be made. The amount of scattering required to make such a measurement possible presently within a few days is indicated and it is shown that at next-generation synchrotron sources this time will be reduced dramatically, i.e. by more than three orders of magnitude. The analytical results are confirmed with simulations in the frame of Gaussian statistics. In the future, this approach could be extended to even shorter time scales with the implementation of ultrafast streak cameras.
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Affiliation(s)
- James Wingert
- Department of Physics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Andrej Singer
- Department of Physics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Oleg G Shpyrko
- Department of Physics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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Schubert M, Schaefer H, Mayer J, Laptev A, Hettich M, Merklein M, He C, Rummel C, Ristow O, Großmann M, Luo Y, Gusev V, Samwer K, Fonin M, Dekorsy T, Demsar J. Collective Modes and Structural Modulation in Ni-Mn-Ga(Co) Martensite Thin Films Probed by Femtosecond Spectroscopy and Scanning Tunneling Microscopy. PHYSICAL REVIEW LETTERS 2015; 115:076402. [PMID: 26317735 DOI: 10.1103/physrevlett.115.076402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Indexed: 06/04/2023]
Abstract
The origin of the martensitic transition in the magnetic shape memory alloy Ni-Mn-Ga has been widely discussed. While several studies suggest it is electronically driven, the adaptive martensite model reproduced the peculiar nonharmonic lattice modulation. We used femtosecond spectroscopy to probe the temperature and doping dependence of collective modes, and scanning tunneling microscopy revealed the corresponding static modulations. We show that the martensitic phase can be described by a complex charge-density wave tuned by magnetic ordering and strong electron-lattice coupling.
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Affiliation(s)
- M Schubert
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - H Schaefer
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
- Institute of Physics, Ilmenau University of Technology, 98693 Ilmenau, Germany
| | - J Mayer
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - A Laptev
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - M Hettich
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - M Merklein
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - C He
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - C Rummel
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - O Ristow
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - M Großmann
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - Y Luo
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37073 Göttingen, Germany
| | - V Gusev
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
- Laboratoire d'Acoustique, LAUM, UMR CNRS 6613, LUNAM Université, Université du Maine, 72085 Le Mans, France
| | - K Samwer
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37073 Göttingen, Germany
| | - M Fonin
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - T Dekorsy
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - J Demsar
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
- Institute of Physics, Ilmenau University of Technology, 98693 Ilmenau, Germany
- Institute of Physics, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
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32
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Porer M, Leierseder U, Ménard JM, Dachraoui H, Mouchliadis L, Perakis IE, Heinzmann U, Demsar J, Rossnagel K, Huber R. Non-thermal separation of electronic and structural orders in a persisting charge density wave. NATURE MATERIALS 2014; 13:857-861. [PMID: 25038729 DOI: 10.1038/nmat4042] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 06/23/2014] [Indexed: 06/03/2023]
Abstract
The simultaneous ordering of different degrees of freedom in complex materials undergoing spontaneous symmetry-breaking transitions often involves intricate couplings that have remained elusive in phenomena as wide ranging as stripe formation, unconventional superconductivity or colossal magnetoresistance. Ultrafast optical, X-ray and electron pulses can elucidate the microscopic interplay between these orders by probing the electronic and lattice dynamics separately, but a simultaneous direct observation of multiple orders on the femtosecond scale has been challenging. Here we show that ultrabroadband terahertz pulses can simultaneously trace the ultrafast evolution of coexisting lattice and electronic orders. For the example of a charge density wave (CDW) in 1T-TiSe2, we demonstrate that two components of the CDW order parameter--excitonic correlations and a periodic lattice distortion (PLD)--respond very differently to 12-fs optical excitation. Even when the excitonic order of the CDW is quenched, the PLD can persist in a coherently excited state. This observation proves that excitonic correlations are not the sole driving force of the CDW transition in 1T-TiSe2, and exemplifies the sort of profound insight that disentangling strongly coupled components of order parameters in the time domain may provide for the understanding of a broad class of phase transitions.
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Affiliation(s)
- M Porer
- Department of Physics, University of Regensburg, 93040 Regensburg, Germany
| | - U Leierseder
- Department of Physics, University of Regensburg, 93040 Regensburg, Germany
| | - J-M Ménard
- Department of Physics, University of Regensburg, 93040 Regensburg, Germany
| | - H Dachraoui
- 1] Molecular and Surface Physics, University of Bielefeld, 33615 Bielefeld, Germany [2]
| | - L Mouchliadis
- Department of Physics, University of Crete and FORTH/IESL, Heraklion, Crete 71110, Greece
| | - I E Perakis
- Department of Physics, University of Crete and FORTH/IESL, Heraklion, Crete 71110, Greece
| | - U Heinzmann
- Molecular and Surface Physics, University of Bielefeld, 33615 Bielefeld, Germany
| | - J Demsar
- Institute of Physics, Ilmenau University of Technology, 98684 Ilmenau, Germany
| | - K Rossnagel
- Institute of Experimental and Applied Physics, University of Kiel, 24098 Kiel, Germany
| | - R Huber
- Department of Physics, University of Regensburg, 93040 Regensburg, Germany
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34
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Huber T, Mariager SO, Ferrer A, Schäfer H, Johnson JA, Grübel S, Lübcke A, Huber L, Kubacka T, Dornes C, Laulhe C, Ravy S, Ingold G, Beaud P, Demsar J, Johnson SL. Coherent structural dynamics of a prototypical charge-density-wave-to-metal transition. PHYSICAL REVIEW LETTERS 2014; 113:026401. [PMID: 25062214 DOI: 10.1103/physrevlett.113.026401] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Indexed: 05/19/2023]
Abstract
Using femtosecond time-resolved x-ray diffraction, we directly monitor the coherent lattice dynamics through an ultrafast charge-density-wave-to-metal transition in the prototypical Peierls system K(0.3)MoO(3) over a wide range of relevant excitation fluences. While in the low fluence regime we directly follow the structural dynamics associated with the collective amplitude mode; for fluences above the melting threshold of the electronic density modulation we observe a transient recovery of the periodic lattice distortion. We can describe these structural dynamics as a motion along the coordinate of the Peierls distortion triggered by the prompt collapse of electronic order after photoexcitation. The results indicate that the dynamics of a structural symmetry-breaking transition are determined by a high-symmetry excited state potential energy surface distinct from that of the initial low-temperature state.
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Affiliation(s)
- T Huber
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - S O Mariager
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - A Ferrer
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland and Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - H Schäfer
- Physics Department, Universität Konstanz, D-78457 Konstanz, Germany
| | - J A Johnson
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - S Grübel
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - A Lübcke
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland and Laboratoire de Spectroscopie Ultrarapide, EPF Lausanne, CH-1015 Lausanne, Switzerland
| | - L Huber
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - T Kubacka
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - C Dornes
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - C Laulhe
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, FR-91192 Gif-sur-Yvette Cedex, France and Université Paris-Sud, 91405 Orsay Cedex, France
| | - S Ravy
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, FR-91192 Gif-sur-Yvette Cedex, France
| | - G Ingold
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - P Beaud
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - J Demsar
- Physics Department, Universität Konstanz, D-78457 Konstanz, Germany and Institute of Physics, Ilmenau University of Technology, D-98693 Ilmenau, Germany
| | - S L Johnson
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
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Miller RJD. Femtosecond crystallography with ultrabright electrons and x-rays: capturing chemistry in action. Science 2014; 343:1108-16. [PMID: 24604195 DOI: 10.1126/science.1248488] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
With the recent advances in ultrabright electron and x-ray sources, it is now possible to extend crystallography to the femtosecond time domain to literally light up atomic motions involved in the primary processes governing structural transitions. This review chronicles the development of brighter and brighter electron and x-ray sources that have enabled atomic resolution to structural dynamics for increasingly complex systems. The primary focus is on achieving sufficient brightness using pump-probe protocols to resolve the far-from-equilibrium motions directing chemical processes that in general lead to irreversible changes in samples. Given the central importance of structural transitions to conceptualizing chemistry, this emerging field has the potential to significantly improve our understanding of chemistry and its connection to driving biological processes.
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Affiliation(s)
- R J Dwayne Miller
- Atomically Resolved Dynamics Division, The Max Planck Institute for the Structure and Dynamics of Matter, The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, Hamburg 22761, Germany
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37
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Lee J, Trugman SA, Batista CD, Zhang CL, Talbayev D, Xu XS, Cheong SW, Yarotski DA, Taylor AJ, Prasankumar RP. Probing the interplay between quantum charge fluctuations and magnetic ordering in LuFe2O4. Sci Rep 2013; 3:2654. [PMID: 24030661 PMCID: PMC3772380 DOI: 10.1038/srep02654] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 08/23/2013] [Indexed: 12/02/2022] Open
Abstract
The mechanisms producing strong coupling between electric and magnetic order in multiferroics are not always well understood, since their microscopic origins can be quite different. Hence, gaining a deeper understanding of magnetoelectric coupling in these materials is the key to their rational design. Here, we use ultrafast optical spectroscopy to show that the influence of magnetic ordering on quantum charge fluctuations via the double-exchange mechanism can govern the interplay between electric polarization and magnetism in the charge-ordered multiferroic LuFe2O4.
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Affiliation(s)
- J Lee
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545
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38
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Erasmus N, Eichberger M, Haupt K, Boshoff I, Kassier G, Birmurske R, Berger H, Demsar J, Schwoerer H. Ultrafast dynamics of charge density waves in 4H(b)-TaSe2 probed by femtosecond electron diffraction. PHYSICAL REVIEW LETTERS 2012; 109:167402. [PMID: 23215128 DOI: 10.1103/physrevlett.109.167402] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Indexed: 05/22/2023]
Abstract
The dynamics of the photoinduced commensurate-to-incommensurate charge density wave (CDW) phase transition in 4H(b)-TaSe(2) are investigated by femtosecond electron diffraction. In the perturbative regime, the CDW re-forms on a 150-ps time scale, which is two orders of magnitude slower than in other transition-metal dichalcogenides. We attribute this to a weak coupling between the CDW carrying T layers and thus demonstrate the importance of three-dimensionality for the existence of CDWs. With increasing optical excitation, the phase transition is achieved, showing a second-order character, in contrast to the first-order behavior in thermal equilibrium.
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Affiliation(s)
- N Erasmus
- Laser Research Institute, Stellenbosch University, Stellenbosch 7600, South Africa
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40
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Abstract
Light-matter interactions are ubiquitous, and underpin a wide range of basic research fields and applied technologies. Although optical interactions have been intensively studied, their microscopic details are often poorly understood and have so far not been directly measurable. X-ray and optical wave mixing was proposed nearly half a century ago as an atomic-scale probe of optical interactions but has not yet been observed owing to a lack of sufficiently intense X-ray sources. Here we use an X-ray laser to demonstrate X-ray and optical sum-frequency generation. The underlying nonlinearity is a reciprocal-space probe of the optically induced charges and associated microscopic fields that arise in an illuminated material. To within the experimental errors, the measured efficiency is consistent with first-principles calculations of microscopic optical polarization in diamond. The ability to probe optical interactions on the atomic scale offers new opportunities in both basic and applied areas of science.
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41
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Hellmann S, Rohwer T, Kalläne M, Hanff K, Sohrt C, Stange A, Carr A, Murnane M, Kapteyn H, Kipp L, Bauer M, Rossnagel K. Time-domain classification of charge-density-wave insulators. Nat Commun 2012; 3:1069. [DOI: 10.1038/ncomms2078] [Citation(s) in RCA: 214] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 08/20/2012] [Indexed: 11/09/2022] Open
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42
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Wall S, Wegkamp D, Foglia L, Appavoo K, Nag J, Haglund RF, Stähler J, Wolf M. Ultrafast changes in lattice symmetry probed by coherent phonons. Nat Commun 2012; 3:721. [PMID: 22395612 DOI: 10.1038/ncomms1719] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 02/01/2012] [Indexed: 11/09/2022] Open
Abstract
The electronic and structural properties of a material are strongly determined by its symmetry. Changing the symmetry via a photoinduced phase transition offers new ways to manipulate material properties on ultrafast timescales. However, to identify when and how fast these phase transitions occur, methods that can probe the symmetry change in the time domain are required. Here we show that a time-dependent change in the coherent phonon spectrum can probe a change in symmetry of the lattice potential, thus providing an all-optical probe of structural transitions. We examine the photoinduced structural phase transition in VO(2) and show that, above the phase transition threshold, photoexcitation completely changes the lattice potential on an ultrafast timescale. The loss of the equilibrium-phase phonon modes occurs promptly, indicating a non-thermal pathway for the photoinduced phase transition, where a strong perturbation to the lattice potential changes its symmetry before ionic rearrangement has occurred.
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Affiliation(s)
- S Wall
- Department of Physical Chemistry, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, Berlin 14195, Germany.
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