Ultrafast carrier and structural dynamics in graphite detected via attosecond soft X-ray absorption spectroscopy

Understanding most of the physical and chemical phenomena determining the world around us requires the possibility to interrogate their main characters on their natural scale in space and time. The insulating or conductive behavior of matter, its magnetic properties or the nature of chemical bonds are strongly dependent on the nuclear and electronic structure of the atoms, molecules or solids considered. Hence, tools are needed to probe electrons and nuclei directly at the atomic scale with a temporal resolution allowing the observation of electron dynamics (on the attosecond-to-femtosecond timescale) and structural dynamics (on the femtosecond-to-picosecond timescale) in real time. Attosecond science offers unique opportunities to investigate electronic and structural dynamics at the heart of important processes in atomic, molecular and solid-state physics. The generation of attosecond bursts of light, in the form of train of pulses or of isolated pulses, has been achieved on table-top sources by exploiting the high-order harmonic generation (HHG) process. The photons constituting the attosecond emission have energies that range from the extreme ultra-violet (XUV) up to the soft X-ray (SXR) region of the spectrum, allowing to interrogate the electronic structure of the probed material directly at the level of the inner electronic shells. Because of this property of accessing the characteristic electronic structure of the elements constituting the target, XUV and, especially, SXR spectroscopy are considered element-specific techniques. Attosecond pulses have already proven to be able to observe ultrafast phenomena in atoms, molecules or solids previously inaccessible. In this thesis, the application of time-resolved X-ray absorption fine-structure (XAFS) spectroscopy using attosecond SXR pulses to the study of carrier and structural dynamics in graphite is reported. In chapter 1, an introduction to the field of attoscience and the presentation of the state of the art of ultrafast dynamics in graphite are given. The established technique to generate attosecond pulses is described and a review of the most significant application of attosecond pulses to the study of electron dynamics is presented. The electronic and structural properties of graphite are then discussed, highlighting some of the most representative experiments detecting electron and lattice dynamics. The experimental setup developed at ICFO in the group of Prof. Dr. Jens Biegert and used for this Ph.D. thesis project is described in details in chapter 2. The system needed for the generation, propagation and detection of the attosecond SXR radiation is presented. The performances of the SXR source in terms of spectral tunability, photon flux and stability are discussed. The implementation of a IR pump - SXR probe scheme is reported, allowing beams' recombination in both collinear and non-collinear fashion. To conclude, the results of an attosecond streaking experiment are presented, through which a temporal characterization of the HHG emission has been achieved. A discussion on the spectroscopic capabilities of XAFS technique to interrogate the electronic and lattice structure of the observed material is presented in chapter 3. The potential of this technique has been demonstrated with an experimental investigation of a graphite thin film, with the results showing the possibility to probe the first unoccupied electronic bands and the characteristic distances defining the lattice structure. Finally, the XAFS capabilities have been exploited in a time-resolved experimental study of graphite to observe light-induced carrier and lattice dynamics, presented in chapter 4. The interpretation of the experimental data reveals insights on the ultrafast interaction of the pump laser field with charge carriers and on the effects of carrier-carrier and carrier-phonon scattering following photoexcitation.Comprender la mayoría de los fenómenos físicos y químicos que determinan el mundo que nos rodea requiere interrogar a sus personajes principales - los átomos, moléculas o sólidos - en el espacio y en el tiempo. Por lo tanto, se necesitan herramientas para investigar el movimiento de los electrones y núcleos atómicos que los componen en tiempo real. Para ello, necesitamos trabajar directamente en su escala natural, es decir, con una resolución temporal de attosegundos en el caso de los electrones y de femtosegundos a picosegundos en el caso de los núcleos. La Attociencia ofrece oportunidades únicas para investigar dinámicas electrónicas y estructurales en el corazón de procesos importantes en física atómica, molecular y del estado sólido. La generación de pulsos de luz de attosegundos se ha logrado en fuentes láseres de laboratorio explotando la generación de armónicos de alto orden (HHG). Los fotones que constituyen las emisiones de as tienen energías que van desde el ultravioleta extremo (XUV) hasta la región de rayos X blandos (SXR) del espectro, lo que permite examinar los niveles electrónicos internos. Los pulsos de attosegundos ya han demostrado ser capaces de observar fenómenos ultrarrápidos y previamente inaccesibles en átomos, moléculas o sólidos. En esta tesis se presenta la aplicación de la espectroscopía de absorción de rayos X (XAFS) resuelta en el tiempo usando pulsos SXR de as para el estudio de dinámicas electrónicas y estructurales en grafito. El capítulo 1 incluye una introducción al campo de la Attociencia y la presentación del estado del arte de las dinámicas ultrarrápidas en grafito. Asimismo, se describe la técnica establecida para generar pulsos de attosegundos y se presenta una revisión de las aplicaciones más significativas de estos pulsos al estudio de las dinámicas electrónicas. A continuación, se explican las propiedades electrónicas y estructurales del grafito, destacando algunos de los experimentos más representativos en detección de dinámicas electrónicas y vibracionales. En el capítulo 2 se describe la metodología experimental desarrollada en el grupo del Prof. Jens Biegert en ICFO y utilizada en esta tesis doctoral. En concreto, se presenta el sistema láser empleado para el proceso HHG para producir la radiación SXR de attosegundos así como el sistema utilizado para la generación, propagación y detección de la radiación. De igual modo, se discuten las propiedades de la fuente SXR en términos de afinación espectral, flujo de fotones y estabilidad. También se presenta la implementación de un sistema “pump-probe” con un pulso de bomba infrarrojo y una sonda SXR, lo que permite la recombinación de haces de manera colineal y no colineal. En último lugar, se presentan los resultados de un experimento de caracterización temporal de la emisión de HHG. A continuación, en el capítulo 3 se presenta una discusión sobre las capacidades espectroscópicas de la técnica XAFS para interrogar la estructura electrónica y vibracional del material en estudio. El potencial de esta técnica se ha demostrado con una investigación experimental sobre grafito, con los resultados que muestran la posibilidad de estudiar las primeras bandas electrónicas desocupadas y las distancias características que definen la estructura del cristal. Finalmente, las capacidades de XAFS han sido utilizadas en un estudio experimental sobre grafito para observar dinámicas electrónicas y vibracionales, desde la escala sub-fs hasta el ps, y se presenta en el capítulo 4. La interpretación de los datos experimentales revela ideas sobre la interacción ultrarrápida del campo eléctrico del láser con electrones, los efectos de dispersión electrón-electrón y electrón-fonón después de la foto-excitación, con el último inducido por el fuerte acoplamiento electrón-fonón en el caso del grafito

Ultrafast carrier and structural dynamics in graphite detected via attosecond soft X-ray absorption spectroscopy

Understanding most of the physical and chemical phenomena determining the world around us requires the possibility to interrogate their main characters on their natural scale in space and time. The insulating or conductive behavior of matter, its magnetic properties or the nature of chemical bonds are strongly dependent on the nuclear and electronic structure of the atoms, molecules or solids considered. Hence, tools are needed to probe electrons and nuclei directly at the atomic scale with a temporal resolution allowing the observation of electron dynamics (on the attosecond-to-femtosecond timescale) and structural dynamics (on the femtosecond-to-picosecond timescale) in real time. Attosecond science offers unique opportunities to investigate electronic and structural dynamics at the heart of important processes in atomic, molecular and solid-state physics. The generation of attosecond bursts of light, in the form of train of pulses or of isolated pulses, has been achieved on table-top sources by exploiting the high-order harmonic generation (HHG) process. The photons constituting the attosecond emission have energies that range from the extreme ultra-violet (XUV) up to the soft X-ray (SXR) region of the spectrum, allowing to interrogate the electronic structure of the probed material directly at the level of the inner electronic shells. Because of this property of accessing the characteristic electronic structure of the elements constituting the target, XUV and, especially, SXR spectroscopy are considered element-specific techniques. Attosecond pulses have already proven to be able to observe ultrafast phenomena in atoms, molecules or solids previously inaccessible. In this thesis, the application of time-resolved X-ray absorption fine-structure (XAFS) spectroscopy using attosecond SXR pulses to the study of carrier and structural dynamics in graphite is reported. In chapter 1, an introduction to the field of attoscience and the presentation of the state of the art of ultrafast dynamics in graphite are given. The established technique to generate attosecond pulses is described and a review of the most significant application of attosecond pulses to the study of electron dynamics is presented. The electronic and structural properties of graphite are then discussed, highlighting some of the most representative experiments detecting electron and lattice dynamics. The experimental setup developed at ICFO in the group of Prof. Dr. Jens Biegert and used for this Ph.D. thesis project is described in details in chapter 2. The system needed for the generation, propagation and detection of the attosecond SXR radiation is presented. The performances of the SXR source in terms of spectral tunability, photon flux and stability are discussed. The implementation of a IR pump - SXR probe scheme is reported, allowing beams' recombination in both collinear and non-collinear fashion. To conclude, the results of an attosecond streaking experiment are presented, through which a temporal characterization of the HHG emission has been achieved. A discussion on the spectroscopic capabilities of XAFS technique to interrogate the electronic and lattice structure of the observed material is presented in chapter 3. The potential of this technique has been demonstrated with an experimental investigation of a graphite thin film, with the results showing the possibility to probe the first unoccupied electronic bands and the characteristic distances defining the lattice structure. Finally, the XAFS capabilities have been exploited in a time-resolved experimental study of graphite to observe light-induced carrier and lattice dynamics, presented in chapter 4. The interpretation of the experimental data reveals insights on the ultrafast interaction of the pump laser field with charge carriers and on the effects of carrier-carrier and carrier-phonon scattering following photoexcitation.Comprender la mayoría de los fenómenos físicos y químicos que determinan el mundo que nos rodea requiere interrogar a sus personajes principales - los átomos, moléculas o sólidos - en el espacio y en el tiempo. Por lo tanto, se necesitan herramientas para investigar el movimiento de los electrones y núcleos atómicos que los componen en tiempo real. Para ello, necesitamos trabajar directamente en su escala natural, es decir, con una resolución temporal de attosegundos en el caso de los electrones y de femtosegundos a picosegundos en el caso de los núcleos. La Attociencia ofrece oportunidades únicas para investigar dinámicas electrónicas y estructurales en el corazón de procesos importantes en física atómica, molecular y del estado sólido. La generación de pulsos de luz de attosegundos se ha logrado en fuentes láseres de laboratorio explotando la generación de armónicos de alto orden (HHG). Los fotones que constituyen las emisiones de as tienen energías que van desde el ultravioleta extremo (XUV) hasta la región de rayos X blandos (SXR) del espectro, lo que permite examinar los niveles electrónicos internos. Los pulsos de attosegundos ya han demostrado ser capaces de observar fenómenos ultrarrápidos y previamente inaccesibles en átomos, moléculas o sólidos. En esta tesis se presenta la aplicación de la espectroscopía de absorción de rayos X (XAFS) resuelta en el tiempo usando pulsos SXR de as para el estudio de dinámicas electrónicas y estructurales en grafito. El capítulo 1 incluye una introducción al campo de la Attociencia y la presentación del estado del arte de las dinámicas ultrarrápidas en grafito. Asimismo, se describe la técnica establecida para generar pulsos de attosegundos y se presenta una revisión de las aplicaciones más significativas de estos pulsos al estudio de las dinámicas electrónicas. A continuación, se explican las propiedades electrónicas y estructurales del grafito, destacando algunos de los experimentos más representativos en detección de dinámicas electrónicas y vibracionales. En el capítulo 2 se describe la metodología experimental desarrollada en el grupo del Prof. Jens Biegert en ICFO y utilizada en esta tesis doctoral. En concreto, se presenta el sistema láser empleado para el proceso HHG para producir la radiación SXR de attosegundos así como el sistema utilizado para la generación, propagación y detección de la radiación. De igual modo, se discuten las propiedades de la fuente SXR en términos de afinación espectral, flujo de fotones y estabilidad. También se presenta la implementación de un sistema “pump-probe” con un pulso de bomba infrarrojo y una sonda SXR, lo que permite la recombinación de haces de manera colineal y no colineal. En último lugar, se presentan los resultados de un experimento de caracterización temporal de la emisión de HHG. A continuación, en el capítulo 3 se presenta una discusión sobre las capacidades espectroscópicas de la técnica XAFS para interrogar la estructura electrónica y vibracional del material en estudio. El potencial de esta técnica se ha demostrado con una investigación experimental sobre grafito, con los resultados que muestran la posibilidad de estudiar las primeras bandas electrónicas desocupadas y las distancias características que definen la estructura del cristal. Finalmente, las capacidades de XAFS han sido utilizadas en un estudio experimental sobre grafito para observar dinámicas electrónicas y vibracionales, desde la escala sub-fs hasta el ps, y se presenta en el capítulo 4. La interpretación de los datos experimentales revela ideas sobre la interacción ultrarrápida del campo eléctrico del láser con electrones, los efectos de dispersión electrón-electrón y electrón-fonón después de la foto-excitación, con el último inducido por el fuerte acoplamiento electrón-fonón en el caso del grafito.Postprint (published version

Ultrafast carrier and structural dynamics in graphite detected via attosecond soft X-ray absorption spectroscopy

Understanding most of the physical and chemical phenomena determining the world around us requires the possibility to interrogate their main characters on their natural scale in space and time. The insulating or conductive behavior of matter, its magnetic properties or the nature of chemical bonds are strongly dependent on the nuclear and electronic structure of the atoms, molecules or solids considered. Hence, tools are needed to probe electrons and nuclei directly at the atomic scale with a temporal resolution allowing the observation of electron dynamics (on the attosecond-to-femtosecond timescale) and structural dynamics (on the femtosecond-to-picosecond timescale) in real time. Attosecond science offers unique opportunities to investigate electronic and structural dynamics at the heart of important processes in atomic, molecular and solid-state physics. The generation of attosecond bursts of light, in the form of train of pulses or of isolated pulses, has been achieved on table-top sources by exploiting the high-order harmonic generation (HHG) process. The photons constituting the attosecond emission have energies that range from the extreme ultra-violet (XUV) up to the soft X-ray (SXR) region of the spectrum, allowing to interrogate the electronic structure of the probed material directly at the level of the inner electronic shells. Because of this property of accessing the characteristic electronic structure of the elements constituting the target, XUV and, especially, SXR spectroscopy are considered element-specific techniques. Attosecond pulses have already proven to be able to observe ultrafast phenomena in atoms, molecules or solids previously inaccessible. In this thesis, the application of time-resolved X-ray absorption fine-structure (XAFS) spectroscopy using attosecond SXR pulses to the study of carrier and structural dynamics in graphite is reported. In chapter 1, an introduction to the field of attoscience and the presentation of the state of the art of ultrafast dynamics in graphite are given. The established technique to generate attosecond pulses is described and a review of the most significant application of attosecond pulses to the study of electron dynamics is presented. The electronic and structural properties of graphite are then discussed, highlighting some of the most representative experiments detecting electron and lattice dynamics. The experimental setup developed at ICFO in the group of Prof. Dr. Jens Biegert and used for this Ph.D. thesis project is described in details in chapter 2. The system needed for the generation, propagation and detection of the attosecond SXR radiation is presented. The performances of the SXR source in terms of spectral tunability, photon flux and stability are discussed. The implementation of a IR pump - SXR probe scheme is reported, allowing beams' recombination in both collinear and non-collinear fashion. To conclude, the results of an attosecond streaking experiment are presented, through which a temporal characterization of the HHG emission has been achieved. A discussion on the spectroscopic capabilities of XAFS technique to interrogate the electronic and lattice structure of the observed material is presented in chapter 3. The potential of this technique has been demonstrated with an experimental investigation of a graphite thin film, with the results showing the possibility to probe the first unoccupied electronic bands and the characteristic distances defining the lattice structure. Finally, the XAFS capabilities have been exploited in a time-resolved experimental study of graphite to observe light-induced carrier and lattice dynamics, presented in chapter 4. The interpretation of the experimental data reveals insights on the ultrafast interaction of the pump laser field with charge carriers and on the effects of carrier-carrier and carrier-phonon scattering following photoexcitation.Comprender la mayoría de los fenómenos físicos y químicos que determinan el mundo que nos rodea requiere interrogar a sus personajes principales - los átomos, moléculas o sólidos - en el espacio y en el tiempo. Por lo tanto, se necesitan herramientas para investigar el movimiento de los electrones y núcleos atómicos que los componen en tiempo real. Para ello, necesitamos trabajar directamente en su escala natural, es decir, con una resolución temporal de attosegundos en el caso de los electrones y de femtosegundos a picosegundos en el caso de los núcleos. La Attociencia ofrece oportunidades únicas para investigar dinámicas electrónicas y estructurales en el corazón de procesos importantes en física atómica, molecular y del estado sólido. La generación de pulsos de luz de attosegundos se ha logrado en fuentes láseres de laboratorio explotando la generación de armónicos de alto orden (HHG). Los fotones que constituyen las emisiones de as tienen energías que van desde el ultravioleta extremo (XUV) hasta la región de rayos X blandos (SXR) del espectro, lo que permite examinar los niveles electrónicos internos. Los pulsos de attosegundos ya han demostrado ser capaces de observar fenómenos ultrarrápidos y previamente inaccesibles en átomos, moléculas o sólidos. En esta tesis se presenta la aplicación de la espectroscopía de absorción de rayos X (XAFS) resuelta en el tiempo usando pulsos SXR de as para el estudio de dinámicas electrónicas y estructurales en grafito. El capítulo 1 incluye una introducción al campo de la Attociencia y la presentación del estado del arte de las dinámicas ultrarrápidas en grafito. Asimismo, se describe la técnica establecida para generar pulsos de attosegundos y se presenta una revisión de las aplicaciones más significativas de estos pulsos al estudio de las dinámicas electrónicas. A continuación, se explican las propiedades electrónicas y estructurales del grafito, destacando algunos de los experimentos más representativos en detección de dinámicas electrónicas y vibracionales. En el capítulo 2 se describe la metodología experimental desarrollada en el grupo del Prof. Jens Biegert en ICFO y utilizada en esta tesis doctoral. En concreto, se presenta el sistema láser empleado para el proceso HHG para producir la radiación SXR de attosegundos así como el sistema utilizado para la generación, propagación y detección de la radiación. De igual modo, se discuten las propiedades de la fuente SXR en términos de afinación espectral, flujo de fotones y estabilidad. También se presenta la implementación de un sistema “pump-probe” con un pulso de bomba infrarrojo y una sonda SXR, lo que permite la recombinación de haces de manera colineal y no colineal. En último lugar, se presentan los resultados de un experimento de caracterización temporal de la emisión de HHG. A continuación, en el capítulo 3 se presenta una discusión sobre las capacidades espectroscópicas de la técnica XAFS para interrogar la estructura electrónica y vibracional del material en estudio. El potencial de esta técnica se ha demostrado con una investigación experimental sobre grafito, con los resultados que muestran la posibilidad de estudiar las primeras bandas electrónicas desocupadas y las distancias características que definen la estructura del cristal. Finalmente, las capacidades de XAFS han sido utilizadas en un estudio experimental sobre grafito para observar dinámicas electrónicas y vibracionales, desde la escala sub-fs hasta el ps, y se presenta en el capítulo 4. La interpretación de los datos experimentales revela ideas sobre la interacción ultrarrápida del campo eléctrico del láser con electrones, los efectos de dispersión electrón-electrón y electrón-fonón después de la foto-excitación, con el último inducido por el fuerte acoplamiento electrón-fonón en el caso del grafito

Attosecond Streaking in the Water Window: A New Regime of Attosecond Pulse Characterization

We report on the first streaking measurement of water-window attosecond pulses generated via high harmonic generation, driven by sub-2-cycle, CEP-stable, 1850 nm laser pulses. Both the central photon energy and the energy bandwidth far exceed what has been demonstrated thus far, warranting the investigation of the attosecond streaking technique for the soft X-ray regime and the limits of the FROGCRAB retrieval algorithm under such conditions. We also discuss the problem of attochirp compensation and issues regarding much lower photo-ionization cross sections compared with the XUV in addition to the fact that several shells of target gases are accessed simultaneously. Based on our investigation, we caution that the vastly different conditions in the soft X-ray regime warrant a diligent examination of the fidelity of the measurement and the retrieval procedure.Comment: 14 Pages, 12 figure

Attosecond dispersive soft X-ray absorption fine structure spectroscopy in graphite

Phase transitions of solids and structural transformations of molecules are canonical examples of important photo-induced processes, whose underlying mechanisms largely elude our comprehension due to our inability to correlate electronic excitation with atomic position in real time. Here, we present a decisive step towards such new methodology based on water-window-covering (284 eV to 543 eV) attosecond soft X-ray pulses that can simultaneously access electronic and lattice parameters via dispersive X-ray absorption fine-structure (XAFS) spectroscopy. We validate attoXAFS with an identification of the {\sigma}* and {\pi}* orbital contributions to the density of states in graphite simultaneously with its lattice's four characteristic bonding distances. This work demonstrates the concept of attoXAFS as a powerful real-time investigative tool which is equally applicable to gas-, liquid- and condensed phase

Time-frequency mapping of two-colour photoemission driven by harmonic radiation

The use of few-femtosecond, extreme ultraviolet (XUV) pulses, produced by high-order harmonic generation, in combination with few-femtosecond infrared (IR) pulses in pump-probe experiments has great potential to disclose ultrafast dynamics in molecules, nanostructures and solids. A crucial prerequisite is a reliable characterization of the temporal properties of the XUV and IR pulses. Several techniques have been developed. The majority of them applies phase reconstruction algorithms to a photoelectron spectrogram obtained by ionizing an atomic target in a pump-probe fashion. If the ionizing radiation is a single harmonic, all the information is encoded in a two-color two-photon signal called sideband (SB). In this work, we present a simplified model to interpret the time-frequency mapping of the SB signal and we show that the temporal dispersion of the pulses directly maps onto the shape of its spectrogram. Finally, we derive an analytical solution, which allows us to propose a novel procedure to estimate the second-order dispersion of the XUV and IR pulses in real time and with no need for iterative algorithms

Treatment of hemophilia: a review of current advances and ongoing issues

Replacement of the congenitally deficient factor VIII or IX through plasma-derived or recombinant concentrates is the mainstay of treatment for hemophilia. Concentrate infusions when hemorrhages occur typically in joint and muscles (on-demand treatment) is able to resolve bleeding, but does not prevent the progressive joint deterioration leading to crippling hemophilic arthropathy. Therefore, primary prophylaxis, ie, regular infusion of concentrates started after the first joint bleed and/or before the age of two years, is now recognized as first-line treatment in children with severe hemophilia. Secondary prophylaxis, whenever started, aims to avoid (or delay) the progression of arthropathy and improve patient quality of life. Interestingly, recent data suggest a role for early prophylaxis also in preventing development of inhibitors, the most serious complication of treatment in hemophilia, in which multiple genetic and environmental factors may be involved. Treatment of bleeds in patients with inhibitors requires bypassing agents (activated prothrombin complex concentrates, recombinant factor VIIa). However, eradication of inhibitors by induction of immune tolerance should be the first choice for patients with recent onset inhibitors. The wide availability of safe factor concentrates and programs for comprehensive care has now resulted in highly satisfactory treatment of hemophilia patients in developed countries. Unfortunately, this is not true for more than two-thirds of persons with hemophilia, who live in developing countries

Attosecond core-level spectroscopy reveals the flow of excitation in a material between light, carriers and phonons

© 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.We use attosecond core-level X-ray spectroscopy to disentangle the spectral and dynamical signatures of energy conversion pathways between photons, charge carriers and the lattice in graphite with attosecond precision and across a picosecond range.Peer ReviewedArticle signat per 19 autors/es: T.P.H. Sidiropoulos1*, N. Di Palo1, D.E. Rivas1,2, S. Severino1, M. Reduzzi1, B. Nandy1, B. Bauerhenne3, S. Krylow3, T. Vasileiadis4, T. Danz5, P. Elliott6,7, S. Sharma6, K. Dewhurst7, C. Ropers5, Y. Joly8, K. M. E. Garcia3, M. Wolf4, R. Ernstorfer4, J. Biegert1,9 // 1 ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain; 2 European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany; 3 Theoretische Physik, FB-10, Universität Kassel, 34132 Kassel, Germany; 4 Fritz Haber Institute of the Max Planck Society, Berlin, Germany; 5 4th Physical Institute - Solids and Nanostructures, University of Göttingen, Germany; 6 Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany; 7 Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany; 8 Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France; 9 ICREA - Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain // * present address: Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, GermanyPostprint (author's final draft

Attosecond state-resolved carrier motion in quantum materials probed by soft x-ray XANES

Recent developments in attosecond technology led to table-top x-ray spectroscopy in the soft x-ray range, thus uniting the element- and state-specificity of core-level x-ray absorption spectroscopy with the time resolution to follow electronic dynamics in real-time. We describe recent work in attosecond technology and investigations into materials such as Si, SiO2, GaN, Al2O3, Ti, and TiO2, enabled by the convergence of these two capabilities. We showcase the state-of-the-art on isolated attosecond soft x-ray pulses for x-ray absorption near-edge spectroscopy to observe the 3d-state dynamics of the semi-metal TiS2 with attosecond resolution at the Ti L-edge (460 eV). We describe how the element- and state-specificity at the transition metal L-edge of the quantum material allows us to unambiguously identify how and where the optical field influences charge carriers. This precision elucidates that the Ti:3d conduction band states are efficiently photo-doped to a density of 1.9 x 1021 cm 3. The light-field induces coherent motion of intra-band carriers across 38% of the first Brillouin zone. Lastly, we describe the prospects with such unambiguous real-time observation of carrier dynamics in specific bonding or anti-bonding states and speculate that such capability will bring unprecedented opportunities toward an engineered approach for designer materials with pre-defined properties and efficiency. Examples are composites of semiconductors and insulators like Si, Ge, SiO2, GaN, BN, and quantum materials like graphene, transition metal dichalcogens, or high-Tc superconductors like NbN or LaBaCuO. Exiting are prospects to scrutinize canonical questions in multi-body physics, such as whether the electrons or lattice trigger phase transitions

A global analysis of Y-chromosomal haplotype diversity for 23 STR loci

In a worldwide collaborative effort, 19,630 Y-chromosomes were sampled from 129 different populations in 51 countries. These chromosomes were typed for 23 short-tandem repeat (STR) loci (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385ab, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635, GATAH4, DYS481, DYS533, DYS549, DYS570, DYS576, and DYS643) and using the PowerPlex Y23 System (PPY23, Promega Corporation, Madison, WI). Locus-specific allelic spectra of these markers were determined and a consistently high level of allelic diversity was observed. A considerable number of null, duplicate and off-ladder alleles were revealed. Standard single-locus and haplotype-based parameters were calculated and compared between subsets of Y-STR markers established for forensic casework. The PPY23 marker set provides substantially stronger discriminatory power than other available kits but at the same time reveals the same general patterns of population structure as other marker sets. A strong correlation was observed between the number of Y-STRs included in a marker set and some of the forensic parameters under study. Interestingly a weak but consistent trend toward smaller genetic distances resulting from larger numbers of markers became apparent.Peer reviewe