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Fechner M, Först M, Orenstein G, Krapivin V, Disa AS, Buzzi M, von Hoegen A, de la Pena G, Nguyen QL, Mankowsky R, Sander M, Lemke H, Deng Y, Trigo M, Cavalleri A. Quenched lattice fluctuations in optically driven SrTiO 3. Nat Mater 2024; 23:363-368. [PMID: 38302742 PMCID: PMC10917662 DOI: 10.1038/s41563-023-01791-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 12/14/2023] [Indexed: 02/03/2024]
Abstract
Crystal lattice fluctuations, which are known to influence phase transitions of quantum materials in equilibrium, are also expected to determine the dynamics of light-induced phase changes. However, they have only rarely been explored in these dynamical settings. Here we study the time evolution of lattice fluctuations in the quantum paraelectric SrTiO3, in which mid-infrared drives have been shown to induce a metastable ferroelectric state. Crucial in these physics is the competition between polar instabilities and antiferrodistortive rotations, which in equilibrium frustrate the formation of long-range ferroelectricity. We make use of high-intensity mid-infrared optical pulses to resonantly drive the Ti-O-stretching mode at 17 THz, and we measure the resulting change in lattice fluctuations using time-resolved X-ray diffuse scattering at a free-electron laser. After a prompt increase, we observe a long-lived quench in R-point antiferrodistortive lattice fluctuations. Their enhancement and reduction are theoretically explained by considering the fourth-order nonlinear phononic interactions to the driven optical phonon and third-order coupling to lattice strain, respectively. These observations provide a number of testable hypotheses for the physics of light-induced ferroelectricity.
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Affiliation(s)
- M Fechner
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany.
| | - M Först
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany.
| | - G Orenstein
- Stanford Pulse Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - V Krapivin
- Stanford Pulse Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - A S Disa
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
- School of Applied & Engineering Physics, Cornell University, Ithaca, NY, USA
| | - M Buzzi
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
| | - A von Hoegen
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
| | - G de la Pena
- Stanford Pulse Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Q L Nguyen
- Stanford Pulse Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - R Mankowsky
- Paul Scherrer Institut, Villigen, Switzerland
| | - M Sander
- Paul Scherrer Institut, Villigen, Switzerland
| | - H Lemke
- Paul Scherrer Institut, Villigen, Switzerland
| | - Y Deng
- Paul Scherrer Institut, Villigen, Switzerland
| | - M Trigo
- Stanford Pulse Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - A Cavalleri
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany.
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK.
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Tkach O, Vo TP, Fedchenko O, Medjanik K, Lytvynenko Y, Babenkov S, Vasilyev D, Nguyen QL, Peixoto TRF, Gloskowskii A, Schlueter C, Chernov S, Hoesch M, Kutnyakhov D, Scholz M, Wenthaus L, Wind N, Marotzke S, Winkelmann A, Rossnagel K, Minár J, Elmers HJ, Schönhense G. Circular dichroism in hard X-ray photoelectron diffraction observed by time-of-flight momentum microscopy. Ultramicroscopy 2023; 250:113750. [PMID: 37178606 DOI: 10.1016/j.ultramic.2023.113750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 04/01/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023]
Abstract
X-ray photoelectron diffraction (XPD) is a powerful technique that yields detailed structural information of solids and thin films that complements electronic structure measurements. Among the strongholds of XPD we can identify dopant sites, track structural phase transitions, and perform holographic reconstruction. High-resolution imaging of kll-distributions (momentum microscopy) presents a new approach to core-level photoemission. It yields full-field kx-ky XPD patterns with unprecedented acquisition speed and richness in details. Here, we show that beyond the pure diffraction information, XPD patterns exhibit pronounced circular dichroism in the angular distribution (CDAD) with asymmetries up to 80%, alongside with rapid variations on a small kll-scale (0.1 Å-1). Measurements with circularly-polarized hard X-rays (hν = 6 keV) for a number of core levels, including Si, Ge, Mo and W, prove that core-level CDAD is a general phenomenon that is independent of atomic number. The fine structure in CDAD is more pronounced compared to the corresponding intensity patterns. Additionally, they obey the same symmetry rules as found for atomic and molecular species, and valence bands. The CD is antisymmetric with respect to the mirror planes of the crystal, whose signatures are sharp zero lines. Calculations using both the Bloch-wave approach and one-step photoemission reveal the origin of the fine structure that represents the signature of Kikuchi diffraction. To disentangle the roles of photoexcitation and diffraction, XPD has been implemented into the Munich SPRKKR package to unify the one-step model of photoemission and multiple scattering theory.
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Affiliation(s)
- O Tkach
- Johannes Gutenberg-Universität, Institut für Physik, 55128 Mainz, Germany; Sumy State University, Rymskogo-Korsakova 2, 40007 Sumy, Ukraine.
| | - T-P Vo
- New Technologies - Research Centre, Univ. of West Bohemia, 30100 Pilsen, Czech Republic
| | - O Fedchenko
- Johannes Gutenberg-Universität, Institut für Physik, 55128 Mainz, Germany
| | - K Medjanik
- Johannes Gutenberg-Universität, Institut für Physik, 55128 Mainz, Germany
| | - Y Lytvynenko
- Johannes Gutenberg-Universität, Institut für Physik, 55128 Mainz, Germany; Institute of Magnetism of the NAS of Ukraine and MES of Ukraine, 03142 Kyiv, Ukraine
| | - S Babenkov
- Johannes Gutenberg-Universität, Institut für Physik, 55128 Mainz, Germany
| | - D Vasilyev
- Johannes Gutenberg-Universität, Institut für Physik, 55128 Mainz, Germany
| | - Q L Nguyen
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - T R F Peixoto
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - A Gloskowskii
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - C Schlueter
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - S Chernov
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - M Hoesch
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - D Kutnyakhov
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - M Scholz
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - L Wenthaus
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - N Wind
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany; Institut für Experimentalphysik, Universität Hamburg, 22761 Hamburg, Germany
| | - S Marotzke
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany; Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - A Winkelmann
- Academic Centre for Materials and Nanotechn., Univ. of Science and Technology, Kraków, Poland
| | - K Rossnagel
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany; Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - J Minár
- New Technologies - Research Centre, Univ. of West Bohemia, 30100 Pilsen, Czech Republic
| | - H-J Elmers
- Johannes Gutenberg-Universität, Institut für Physik, 55128 Mainz, Germany
| | - G Schönhense
- Johannes Gutenberg-Universität, Institut für Physik, 55128 Mainz, Germany
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Lefebvre MA, Pham DM, Boussouira B, Qiu H, Ye C, Long X, Chen R, Gu W, Laurent A, Nguyen QL. Consequences of urban pollution upon skin status. A controlled study in Shanghai area. Int J Cosmet Sci 2015; 38:217-23. [PMID: 26291783 DOI: 10.1111/ics.12270] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 08/12/2015] [Indexed: 12/17/2022]
Abstract
OBJECTIVE After preliminary studies aimed at measuring pertinent biochemical parameters, potentially modified in subjects exposed to bad environmental conditions, a dedicated study was performed in Shanghai city to evaluate the effect of Urban pollution upon human skin and to collect feedback from the volunteers under study. METHODS This study was performed during summer 2008 in two different districts of Shanghai, on 159 local residents: 79 subjects from Xu Jia Hui (a centre Shanghainese area), more exposed to pollution, and 80 subjects from Chong Ming, an agricultural region closely located north of Shanghai (<100 kms) and less exposed to pollution, according to official data. Biochemical parameters were measured on skin, and feedback from volunteers was collected through a graduated 'Likert scale' questionnaire under a point scale (strongly agree, agree, disagree, strongly disagree and none). RESULTS The study demonstrated significant differences in several biochemical parameters measured in Chong Ming area, as compared to Urban area, with an increased ratio of squalene/lipids, a lower level of lactic acid and a better cohesion of stratum corneum. Both sebum excretion rate and sebum casual levels did not differ between the two districts. The volunteer's feedback evidenced a perceived link between pollution and their skin problems. CONCLUSION This study demonstrated a significant impact of the pollution upon the skin status, as illustrated by changes in superficial biochemical parameters and volunteers' perception.
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Affiliation(s)
- M-A Lefebvre
- L'Oreal Research & Innovation, 11-13 rue Dora Mar, 93400, Saint-Ouen, France
| | - D-M Pham
- L'Oreal Research & Innovation, 188 rue Paul Hochart BP 553, 94152, Chevilly-Larue, France
| | - B Boussouira
- L'Oreal Research & Innovation, 188 rue Paul Hochart BP 553, 94152, Chevilly-Larue, France
| | - H Qiu
- L'Oreal Research & Innovation, No. 550 JinYu Rd., Pudong New Area, Shanghai, China
| | - C Ye
- L'Oreal Research & Innovation, No. 550 JinYu Rd., Pudong New Area, Shanghai, China
| | - X Long
- L'Oreal Research & Innovation, No. 550 JinYu Rd., Pudong New Area, Shanghai, China
| | - R Chen
- L'Oreal Research & Innovation, No. 550 JinYu Rd., Pudong New Area, Shanghai, China
| | - W Gu
- L'Oreal Research & Innovation, No. 550 JinYu Rd., Pudong New Area, Shanghai, China
| | - A Laurent
- L'Oreal Research & Innovation, No. 550 JinYu Rd., Pudong New Area, Shanghai, China
| | - Q-L Nguyen
- L'Oreal Research & Innovation, 188 rue Paul Hochart BP 553, 94152, Chevilly-Larue, France
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Lefebvre MA, Pham DM, Boussouira B, Bernard D, Camus C, Nguyen QL. Evaluation of the impact of urban pollution on the quality of skin: a multicentre study in Mexico. Int J Cosmet Sci 2015; 37:329-38. [PMID: 25655908 DOI: 10.1111/ics.12203] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 01/24/2015] [Indexed: 01/06/2023]
Abstract
OBJECTIVE After pilot and preliminary studies aimed at identifying pertinent biochemical parameters, a multicenter clinical study was performed to evaluate the effect of pollution on human skin. METHODS The clinical study was performed in collaboration with the 'Centre Régional de lutte contre le cancer de Montpellier' and the 'National Institute of Public Health of Mexico' on 96 subjects in Mexico City (exposed to pollution) and 93 subjects in Cuernavaca (less exposed to pollution). Both biochemical and clinical skin parameters were studied. RESULTS The study demonstrated significant quantitative and qualitative modifications of parameters related to sebum excretion in Mexico City compared to Cuernavaca one: An increased level of sebum excretion rate, a lower level of vitamin E and squalene in sebum, an increase of lactic acid and a higher erythematous index on the face of the subjects. In the stratum corneum, a significant higher level of carbonylated proteins and a lower level of IL 1α were noticed, as well as a decrease of ATP concentration with a decrease of chymotrysin like activity, without modifications of corneodesmosin content and trypsin like activity. From a clinical point of view, a higher frequency of atopic and urticarial skins, a higher frequency of red dermographism, an important seborrheic status at the forehead level and a lower level of dandruffs were noted in Mexico City population. The analysis taking into account the sex does not modify the observed results. CONCLUSION The study demonstrated an important impact of polluted environmental conditions on skin quality, evidencing important modifications of superficial biochemical parameters. The cause/effects relationships of these modifications remain, however, to be further assessed by a complementary in vitro/in vivo approaches.
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Affiliation(s)
- M-A Lefebvre
- L'Oreal Research & Innovation, 11-13 rue Dora Mar, 93400, Saint-Ouen, France
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Pham DM, Boussouira B, Moyal D, Nguyen QL. Oxidization of squalene, a human skin lipid: a new and reliable marker of environmental pollution studies. Int J Cosmet Sci 2015; 37:357-65. [PMID: 25656265 DOI: 10.1111/ics.12208] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 01/13/2015] [Indexed: 11/28/2022]
Abstract
A review of the oxidization of squalene, a specific human compound produced by the sebaceous gland, is proposed. Such chemical transformation induces important consequences at various levels. Squalene by-products, mostly under peroxidized forms, lead to comedogenesis, contribute to the development of inflammatory acne and possibly modify the skin relief (wrinkling). Experimental conditions of oxidation and/or photo-oxidation mechanisms are exposed, suggesting that they could possibly be bio-markers of atmospheric pollution upon skin. Ozone, long UVA rays, cigarette smoke… are shown powerful oxidizing agents of squalene. Some in vitro, ex vivo and in vivo testings are proposed as examples, aiming at studying ingredients or products capable of boosting or counteracting such chemical changes that, globally, bring adverse effects to various cutaneous compartments.
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Affiliation(s)
- D-M Pham
- L'Oreal Research & Innovation, 188 rue Paul Hochart BP 553, 94152, Chevilly Larue, France
| | - B Boussouira
- L'Oreal Research & Innovation, 188 rue Paul Hochart BP 553, 94152, Chevilly Larue, France
| | - D Moyal
- L'Oreal Research & Innovation, 25-29 Quai Aulagnier, 92665, Asnières-Sur-Seine, France
| | - Q L Nguyen
- L'Oreal Research & Innovation, 188 rue Paul Hochart BP 553, 94152, Chevilly Larue, France
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