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\"Over the last 25 years, dynamical mean-field theory (DMFT) has emerged as one of the most powerful new developments in many-body physics. Written by one of the key researchers in the field, this book presents the first comprehensive treatment of this ever-developing topic. Transport in Mutlilayered Nanostructures is varied and modern in its scope, and: Develops the formalism of many-body Green's functions using the equation-of-motion approach Applies DMFT to study transport in multilayered nanostructures, which is likely to be one of the most prominent applications of nanotechnology in the coming years Develops formalism first for the bulk and then for the inhomogeneous multilayered systems Describes in great detail the science behind the metal-insulator transition, electronic charge reconstruction, strongly correlated contributions to capacitance, and superconductivity Includes complete derivations and emphasizes how to carry out numerical calculations, including discussions of parallel programming algorithms Provides descriptions of the crossover from tunneling to thermally activated transport, of the properties of Josephson junctions with barriers tuned near the metal-insulator transition of thermoelectric coolers and power generators and of nonequilibrium extensions to determine current-voltage characteristics as applications of the theory A series of over 40 problems help develop the skills to allow readers to reach the level of being able to contribute to research. This book is suitable for an advanced graduate course in DMFT, and for individualized study by graduate students, postdoctoral fellows and advanced researchers wishing to enter the field\"-- Provided by publisher.

All-solid-state batteries (SSBs) are one of the most fascinating next-generation energy storage systems that can provide improved energy density and safety for a wide range of applications from portable electronics to electric vehicles. The development of SSBs was accelerated by the discovery of new materials and the design of nanostructures. In particular, advances in the growth of thin-film battery materials facilitated the development of all solid-state thin-film batteries (SSTFBs)—expanding their applications to microelectronics such as flexible devices and implantable medical devices. However, critical challenges still remain, such as low ionic conductivity of solid electrolytes, interfacial instability and difficulty in controlling thin-film growth. In this review, we discuss the evolution of electrode and electrolyte materials for lithium-based batteries and their adoption in SSBs and SSTFBs. We highlight novel design strategies of bulk and thin-film materials to solve the issues in lithium-based batteries. We also focus on the important advances in thin-film electrodes, electrolytes and interfacial layers with the aim of providing insight into the future design of batteries. Furthermore, various thin-film fabrication techniques are also covered in this review.

Increasing performance demands and shorter use lifetimes of consumer electronics have resulted in the rapid growth of electronic waste. Currently, consumer electronics are typically made with nondecomposable, nonbiocompatible, and sometimes even toxic materials, leading to serious ecological challenges worldwide. Here, we report an example of totally disintegrable and biocompatible semiconducting polymers for thin-film transistors. The polymer consists of reversible imine bonds and building blocks that can be easily decomposed under mild acidic conditions. In addition, an ultrathin (800-nm) biodegradable cellulose substrate with high chemical and thermal stability is developed. Coupled with iron electrodes, we have successfully fabricated fully disintegrable and biocompatible polymer transistors. Furthermore, disintegrable and biocompatible pseudo-complementary metal–oxide–semiconductor (CMOS) flexible circuits are demonstrated. These flexible circuits are ultrathin (<1 μm) and ultralightweight (∼2 g/m²) with low operating voltage (4 V), yielding potential applications of these disintegrable semiconducting polymers in low-cost, biocompatible, and ultralightweight transient electronics.

Topologically nontrivial spin textures have recently been investigated for spintronic applications. Here, we report on an ultrathin magnetic film in which individual skyrmions can be written and deleted in a controlled fashion with local spin-polarized currents from a scanning tunneling microscope. An external magnetic field is used to tune the energy landscape, and the temperature is adjusted to prevent thermally activated switching between topologically distinct states. Switching rate and direction can then be controlled by the parameters used for current injection. The creation and annihilation of individual magnetic skyrmions demonstrates the potential for topological charge in future information-storage concepts.

In perovskite solar cells, the interfaces between the perovskite and charge-transporting layers contain high concentrations of defects (about 100 times that within the perovskite layer), specifically, deep-level defects, which substantially reduce the power conversion efficiency of the devices 1 – 3 . Recent efforts to reduce these interfacial defects have focused mainly on surface passivation 4 – 6 . However, passivating the perovskite surface that interfaces with the electron-transporting layer is difficult, because the surface-treatment agents on the electron-transporting layer may dissolve while coating the perovskite thin film. Alternatively, interfacial defects may not be a concern if a coherent interface could be formed between the electron-transporting and perovskite layers. Here we report the formation of an interlayer between a SnO 2 electron-transporting layer and a halide perovskite light-absorbing layer, achieved by coupling Cl-bonded SnO 2 with a Cl-containing perovskite precursor. This interlayer has atomically coherent features, which enhance charge extraction and transport from the perovskite layer, and fewer interfacial defects. The existence of such a coherent interlayer allowed us to fabricate perovskite solar cells with a power conversion efficiency of 25.8 per cent (certified 25.5 per cent)under standard illumination. Furthermore, unencapsulated devices maintained about 90 per cent of their initial efficiency even after continuous light exposure for 500 hours. Our findings provide guidelines for designing defect-minimizing interfaces between metal halide perovskites and electron-transporting layers. An atomically coherent interlayer between the electron-transporting and perovskite layers in perovskite solar cells enhances charge extraction and transport from the perovskite, enabling high power conversion efficiency.

Multiple exciton generation (MEG) refers to the creation of two or more electron-hole pairs from the absorption of one photon. Although MEG holds great promise, it has proven challenging to implement, and questions remain about the underlying photo-physical dynamics in nanocrystalline as well as molecular media. Using the model system of pentacene/fullerene bilayers and femtosecond nonlinear spectroscopies, we directly observed the multiexciton (ME) state ensuing from singlet fission (a molecular manifestation of MEG) in pentacene. The data suggest that the state exists in coherent superposition with the singlet populated by optical excitation. We also found that multiple electron transfer from the ME state to the fullerene occurs on a subpicosecond time scale, which is one order of magnitude faster than that from the triplet exciton state.

With the rapid development of advanced technologies in the Internet of Things era, higher requirements are needed for next‐generation electronic devices. Fortunately, organic thin film transistors (OTFTs) provide an effective solution for electronic skin and flexible wearable devices due to their intrinsic features of mechanical flexibility, lightweight, simple fabrication process, and good biocompatibility. So far considerable efforts have been devoted to this research field. This article reviews recent advances in various promising and state‐of‐the‐art OTFTs as well as related integrated circuits with the main focuses on: (I) material categories of high‐mobility organic semiconductors for both individual transistors and integrated circuits; (II) effective device architectures and processing techniques for large‐area fabrication; (III) important performance metrics of organic integrated circuits and realization of digital and analog devices for future smart life; (IV) applicable analytical models and design flow to accelerate the circuit design. In addition, the emerging challenges of OTFT‐based integrated circuits, such as transistor uniformity and stability are also discussed, and the possible methods to solve these problems at both transistor and circuit levels are summarized. Organic thin film transistors (OTFTs) hold great potential for future smart life due to their intrinsic features of mechanical flexibility, lightweight, simple fabrication process, and good biocompatibility. This article reviews recent advances in various promising and state‐of‐the‐art OTFTs as well as related integrated circuits with the main focus on high‐performance material categories, device architectures and processing techniques, digital and analog devices, and analytical models and design flow. Additionally, the emerging challenges of OTFT‐based integrated circuits and possible solutions are also discussed.

Multiferroics made easier Ferroelectric ferromagnets, or multiferroics, are of significant technological interest because they combine the low power and high speed of field-effect electronics with the permanence and routability of voltage-controlled ferromagnetism. Unfortunately, they are rare, and those that do exist have ferroelectric and ferromagnetic properties that are typically weak compared with conventional useful ferroelectrics and ferromagnets. A new route to fabricating multiferroics was recently predicted: in theory, magnetically ordered insulators that are neither ferroelectric nor ferromagnetic — of which there are many — can be turned into ferroelectric multiferroics by strain from the underlying substrate. June Hyuk Lee et al . now realize this route experimentally for EuTiO3. Their demonstration that a single experimental parameter, strain, can simultaneously control multiple order parameters opens up exciting possibilities for creating useful multiferroic materials. Ferroelectric ferromagnets — materials that are both ferroelectric and ferromagnetic — are of significant technological interest. But they are rare, and those that do exist have weak ferroelectric and ferromagnetic properties. Recently a new way of fabricating such materials was proposed, involving strain from the underlying substrate. This route has now been realized experimentally for EuTiO 3 . The work shows that a single experimental parameter, strain, can simultaneously control multiple order parameters. Ferroelectric ferromagnets are exceedingly rare, fundamentally interesting multiferroic materials that could give rise to new technologies in which the low power and high speed of field-effect electronics are combined with the permanence and routability of voltage-controlled ferromagnetism 1 , 2 . Furthermore, the properties of the few compounds that simultaneously exhibit these phenomena 1 , 2 , 3 , 4 , 5 are insignificant in comparison with those of useful ferroelectrics or ferromagnets: their spontaneous polarizations or magnetizations are smaller by a factor of 1,000 or more. The same holds for magnetic- or electric-field-induced multiferroics 6 , 7 , 8 . Owing to the weak properties of single-phase multiferroics, composite and multilayer approaches involving strain-coupled piezoelectric and magnetostrictive components are the closest to application today 1 , 2 . Recently, however, a new route to ferroelectric ferromagnets was proposed 9 by which magnetically ordered insulators that are neither ferroelectric nor ferromagnetic are transformed into ferroelectric ferromagnets using a single control parameter, strain. The system targeted, EuTiO 3 , was predicted to exhibit strong ferromagnetism (spontaneous magnetization, ∼7 Bohr magnetons per Eu) and strong ferroelectricity (spontaneous polarization, ∼10 µC cm −2 ) simultaneously under large biaxial compressive strain 9 . These values are orders of magnitude higher than those of any known ferroelectric ferromagnet and rival the best materials that are solely ferroelectric or ferromagnetic. Hindered by the absence of an appropriate substrate to provide the desired compression we turned to tensile strain. Here we show both experimentally and theoretically the emergence of a multiferroic state under biaxial tension with the unexpected benefit that even lower strains are required, thereby allowing thicker high-quality crystalline films. This realization of a strong ferromagnetic ferroelectric points the way to high-temperature manifestations of this spin–lattice coupling mechanism 10 . Our work demonstrates that a single experimental parameter, strain, simultaneously controls multiple order parameters and is a viable alternative tuning parameter to composition 11 for creating multiferroics.