Bøker i Springer Theses-serien

This book focuses on the creation and demonstration of a carbon¿carbon (C¿C) single bond beyond 1.8 Å and on elucidation of its unique nature. C¿C single bond is one of the most fundamental concepts in organic chemistry. The elucidation of its nature is important for further understanding chemical phenomena. The nature in the extreme state of C¿C single bond is still unexplored because of the instability of compounds. In terms of its bond length, the limit had been predicted around 1.8 Å based on the experimental and theoretical studies. This book describes a first example of a C¿C single bond beyond 1.8 Å by employing the original intramolecular core-shell strategy to make a weak and elongated bond stable enough. The presence of such an elongated bond was demonstrated by experimental and theoretical studies. The bond length changes could affect physical properties such as optical absorption and redox potential. Furthermore, its unique "flexibility" was discovered. This book benefits the chemists with deeper understanding of the covalent bonding.

This thesis presents the first successful realization of a compact, low-noise, and few-cycle light source in the mid-infrared wavelength region. By developing the technology of pumping femtosecond chromium-doped II-VI laser oscillators directly with the emission of broad-stripe single-emitter laser diodes, coherent light was generated with exceptionally low amplitude noise ¿ crucial for numerous applications including spectroscopy at high sensitivities. Other key parameters of the oscillator's output, such as pulse duration and output power, matched and even surpassed previous state-of-the-art systems. As a demonstration of its unique capabilities, the oscillator's powerful output was used to drive ¿ without further amplification ¿ the nonlinear generation of coherent mid-infrared light spanning multiple octaves. The resulting table-top system uniquely combines high brilliance and ultrabroad spectral bandwidth in the important mid-infrared spectral range.The rapid development of this technology is comprehensively and lucidly documented in this PhD thesis. Together with a thorough review of literature and applications, and an extensive analysis of the theoretical foundations behind ultrafast laser oscillators, the thesis will serve as a valuable reference for the construction of a new generation of mid-infrared light sources.

This book provides a series of methods for flexibly and actively manipulating thermal emission and photoluminance by advanced nanostructures-metamaterials. Nanostructures in subwavelength scales can be designed to precisely modulate light-matter interactions and thereby tailoring both thermal radiations and photon emissions. This book explores approaches for designing different kinds of nanostructures, including multilayers, gratings, nanoridges, and waveguides, to improve the flexibility and functionality of micro/nanodevices. With the help of these subwavelength nanostructures, thermal radiation and photoluminescence have been fully manipulated in near and far fields regarding to the intensity, spectrum, polarization, and direction. The proposed methods together with designed metamaterials open new avenues for designing novel micro-/nanodevices or systems for promising applications like thermal energy harvesting, detecting, sensing, and on-chip quantum-optical networks.

Meso- to Neoarchean is a critical transitional period for the formation and evolution of continental crust and the corresponding geodynamic mechanisms, during which the average composition of continental crust gradually shifted from Na-enriched to K-enriched. However, the ultimate source of K and its enrichment mechanism in continental crust are still enigmatic. Moreover, fierce controversies remain on the Precambrian subdivision and late Archean geodynamic models of the North China Craton (NCC). Archean basement terranes in the Eastern Hebei-Western Liaoning Provinces, northern NCC display characteristic lithological zonation similar to those developed in modern convergent plate margins, and from northwest to southeast can be subdivided into the MORB-type tholeiite belt, oceanic arc tectonic belt, and K-rich granitoid belt. This book reports systematic field geological, petrographic, structural, whole-rock geochemical, and zircon U-Pb-Hf-O isotopic data for the various late Neoarchean lithological assemblages of the K-rich granitoid belt. Their deformational characteristics and petrogenesis are discussed in detail, and integrated with their spatiotemporal relationships and metamorphic features, a late Neoarchean active continental margin setting with multi-stage trench retreats and subsequent arc-continent collision is proposed to account for the formation and evolution of the K-rich granitoid belt. It also throws light upon the ultimate source and enrichment mechanism of K in the late Archean continental crust by comparing K-rich granitoid belt with the adjacent oceanic arc tectonic belt.

This book presents experimental studies on emergent transport and magneto-optical properties in three-dimensional topological insulators with two-dimensional Dirac fermions on their surfaces. Designing magnetic heterostructures utilizing a cutting-edge growth technique (molecular beam epitaxy) stabilizes and manifests new quantization phenomena, as confirmed by low-temperature electrical transport and time-domain terahertz magneto-optical measurements. Starting with a review of the theoretical background and recent experimental advances in topological insulators in terms of a novel magneto-electric coupling, the author subsequently explores their magnetic quantum properties and reveals topological phase transitions between quantum anomalous Hall insulator and trivial insulator phases; a new topological phase (the axion insulator); and a half-integer quantum Hall state associated with the quantum parity anomaly. Furthermore, the author shows how these quantum phases can be significantly stabilized via magnetic modulation doping and proximity coupling with a normal ferromagnetic insulator. These findings provide a basis for future technologies such as ultra-low energy consumption electronic devices and fault-tolerant topological quantum computers.

This book presents the latest theoretical studies giving new predictions and interpretations on the quantum correlation in molecular dynamics induced by ultrashort laser pulses. The author quantifies the amount of correlation in terms of entanglement by employing methods developed in quantum information science, in particular applied to the photoionization of a hydrogen molecule. It is also revealed that the photoelectron-ion correlation affects the vibrational dynamics of the molecular ion and induces the attosecond-level time delay in the molecular vibration. Furthermore, the book also presents how molecular vibration can couple to photons in a plasmoic nanocavity.Physicists and chemists interested in the ultrafast molecular dynamics would be the most relevant readers. They can learn how we can employ the quantum-information-science tools to understand the correlation in the molecular dynamics and why we should consider the correlation between the photoelectron and the molecular ion to describe the ion's dynamics. They can also learn how to treat a molecule coupled to photons in a nanocavity. All the topics are related to the state-of-the-art experiments, and so, it is important to publish these results to enhance the understanding and to induce new experiments to confirm the theory presented. 

The energy momentum tensor (EMT) is one of the most fundamental observables in physics. Recently, a novel method to define EMT on the basis of the gradient-flow formalism has been proposed. It turned out that the EMT operator can be constructed even on the lattice with the method, which enables non-perturbative computations. This approach has been successfully applied to the analyses on thermodynamic quantities.This book presents the study on spatial EMT distributions around static charges via the gradient flow in lattice simulations based on SU(3) Yang-Mills theory. Static charges are employed as probes to explore complex quantum systems, and EMT then characterizes the response of vacuum as well as hot medium under the existence of the charges, which significantly provides profound and novel insights into the non-perturbative phenomena, such as the confinement of quarks. In addition, the book treats the study on the EMT distribution around a magnetic vortex in the Abelian-Higgs model, which is compared with the lattice result. These achievements open up various future studies for revealing non-trivial aspects of the strong interaction.The book also includes well-organized reviews on general properties of EMT, lattice gauge theory and the gradient-flow formalism with its application to the definition of EMT. They are useful for students and young researchers as a brief introduction to this field. 

This book presents the kinematic earthquake rupture studies from moment tenor to spatial-temporal rupture imaging. For real-time seismic hazard monitoring, the new stable automatic moment tensor (AutoBATS) algorithm is developed and implemented for the real-time MT reports by the Taiwan Earthquake Science Information System (TESIS). In order to understand the rupture behavior of the 2013 Mw 8.3 Okhotsk deep earthquake sequence, the 3D MUltiple SIgnal Classification Back Projection (MUSIC BP) with P and pP phases is applied. The combined P- and pP-wave BP imaging of the mainshock shows two stages of anti-parallel ruptures along two depths separating for about 10~15 km. Unusual super-shear ruptures are observed through the 3D BP images of two Mw 6.7 aftershocks. In last two chapters, the 3D BP imaging reveals similar rupture properties of two shallow catastrophic earthquakes (Mw=6.4) in southwestern Taiwan. Both the 2010 Jiashian and 2016 Meinong earthquakes ruptured westward with similar velocity of ~2.5 km/s along a NE-ward shallow dipping blind fault. The rupture similarities of the doublet suggest two parallel elongate asperities along the causative fault. After several decades of seismic quiescence, the 2010 Jiashian event initiated the rupture at the deeper asperity and triggered the shallower asperity which caused catastrophes six years later.

This thesis provides the first atomic length-scale observation of the structural transformation (referred to as lattice reconstruction) that occurs in moire superlattices of twisted bilayer transition metal dichalcogenides (TMDs) at low (I < 2Es) twist angles. Such information is essential for the fundamental understanding of how manipulating the rotational twist-angle between two adjacent 2-dimensional crystals subsequently affects their optical and electrical properties.Studies using Scanning transmission electron microscopy (STEM), a powerful tool for atomic-scale imaging, were limited due to the complexity of the (atomically-thin) sample fabrication requirements. This work developed a unique way to selectively cut and re-stack monolayers of TMDs with a controlled rotational twist angle which could then be easily suspended on a TEM grid to meet the needs of the atomically thin sample requirements. The fabrication technique enabled the study of the two common stacking-polytypes including 3R and 2H (using MoS2 and WS2 as the example) as well as their structural evolution with decreasing twist-angle.Atomic-scale studies were followed by a comprehensive investigation of their electronic properties using scanning probe microscopy and electrical transport measurements of the artificially-engineered structures. The electronic structure of two common stacking-polytypes (3R and 2H) were strikingly different, as revealed by conductive atomic force microscopy. Further studies focused on the 3R-stacking polytype to reveal room-temperature out-of-plane ferroelectricity using tools such as kelvin probe force microscopy, scanning electron microscopy and electrical transport measurements. This work highlights that the unique intrinsic properties of TMDs (i.e. semiconductors with strongly light-matter interaction) combined with the additional twisted degree-of-freedom has great potential to create atomically thin transistors/LEDs with built-in memory storage functions and will further aid in the development of the next generation of optoelectronics.

This PhD thesis reports on investigations of several oxide-based materials using advanced infrared and Raman spectroscopy techniques and in combination with external stimuli such as high magnetic or electric field, sptial confinement in thin film heterostructures and the radiation with UV light. This leads to new results in the fields of superconductivity, electronic polarization states and nanoscale phenomena.Among these, the observation of anomalous polar moments is of great relevance for understanding the electric-field-induced metal-to-insulator transistion; and the demonstration that confocal Raman spectroscopy of backfolded acoustic photons in metal-oxide multilayers  can be used as a powerful characterization tool for monitoring their interface properties and layer thickness is an important technical development for the engineering of such functional oxide heterostructures. 

This thesis addresses the feasibility of the production of ultra-high-energy cosmic rays in starburst galaxies and active galactic nuclei. These astrophysical objects were theoretically proposed as candidate sources a long time ago. Nevertheless, the interest in them has been recently renewed due to the observational data collected by the Pierre Auger Observatory and the Telescope Array. In this work, a comprehensive review of the current status of the research on cosmic rays accelerators is provided, along with a summary of the principal concepts needed to connect these relativistic particles with electromagnetic and neutrino observations in the multi-messenger era. On one hand, the hypothesis of accelerating particles with energies above 10' eV in starburst superwinds is carefully revisited, taking into account the constraints imposed by the most recent electromagnetic observations. On the other hand, an alternative new model for the gamma emission of the nearby active galaxy NGC 1068 is presented. The implications of the results of these studies are discussed in terms of the contemporary observatories and prospects for future experiments are offered.

This book presents novel observational evidence toward detecting and characterizing the products of massive, interacting binary stars. As a majority of massive stars are born in close binary systems, a large number of so-called massive binary interaction products are predicted to exist; however, few have been identified so far. Based on observations with the largest telescopes around the world, equipped with state-of-the-art instrumentation, this book helps to remedy this situation. In her outstanding PhD-thesis Julia Bodensteiner identifies a new class of post-interaction binaries in a short-lived phase just briefly after the initially more massive star has been stripped of part of its envelope. She further provides new evidence for the Be phenomenon to largely result from binary interactions. These results represented a new and testable prediction for the evolution of these stars and opened up a new way forward for identifying hundreds of post-interaction products.Finally, using the MUSE integral field spectrograph at the Very Large Telescope in Chile, the author presents a novel spectroscopic campaign focusing on the 40 Myr-old star cluster NGC 330 in the Small Magellanic Clouds. Combined with photometric observations from the Hubble Space Telescope, the MUSE data allow to characterize the entire massive star population of NGC 330, revealing their multiplicity properties and rotational velocities and providing unique observational constraints on their (binary) evolution history. This is made possible by the developments of novel numerical methods allowing to extract star spectra from the MUSE integral field spectroscopic data and to characterize their properties by the simultaneous comparison of MUSE spectroscopy and Hubble photometry with atmospheric models.This book is a partly re-written version of the author's thesis offering a highly readable coherent text presenting not only new insights into the properties of binary interaction products but also giving students an excellent introduction into the field.