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The history of semiconductors is presented beginning with the first documented observation of a semiconductor effect (Faraday), through the development of the first devices (point-contact rectifiers and transistors, early field-effect transistors) and the theory of semiconductors up to the contemporary devices (SOI and multigate devices).

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In this review, the key issues that how to observe, understand, design, and use catalytic effect in Li-S batteries are systematically discussed. A research paradigm for catalytic effect is further proposed, which will enlighten the future development of Li-S batteries and other next-generation batteries based on conversion reactions. [Display omitted] Lithium-sulfur (Li-S) batteries with high energy density have been considered one kind of promising next-generation energy storage system. However, the shuttling effect of polysulfides caused by the intrinsic sluggish reaction kinetics severely hinders their commercialization. The catalytic effect, a powerful solution towards polysulfides shuttling by accelerating the conversion of polysulfides, has aroused great attention. Numerous catalysts have been developed and proved to have catalytic effects in the past years. More importantly, many advanced in-situ characterization technologies and electronic structure analyses have been combined to study the "black box" of the catalytic process, which promotes the practical application of Li-S batteries entering a new stage. In this review, instead of summarizing recent achievements in catalyst materials and structural designs, the key issues that how to observe, understand, design, and use catalytic effect in Li-S batteries are systematically discussed. In-situ techniques are summarized to see the actual catalytic process. Band theory is applied to understand the electronic structure, thus deciphering design principles and strategies of catalytic effect. Subsequently, how to use the catalytic effect to realize Ah-level Li-S pouch cells is analyzed. Last, we propose a research paradigm for catalytic effect, which will enlighten the future development of Li-S batteries and other next-generation batteries based on conversion reactions. [ABSTRACT FROM AUTHOR]

Hyperbolic lattices are a new form of synthetic quantum matter in which particles effectively hop on a discrete tessellation of two-dimensional (2D) hyperbolic space, a non-Euclidean space of uniform negative curvature. To describe the single-particle eigenstates and eigenenergies for hopping on such a lattice, a hyperbolic generalization of band theory was previously constructed, based on ideas from algebraic geometry. In this hyperbolic band theory, eigenstates are automorphic functions, and the Brillouin zone is a higher-dimensional torus, the Jacobian of the compactified unit cell understood as a higher-genus Riemann surface. Three important questions were left unanswered: whether a band theory can be expected to hold for a non-Euclidean lattice, where translations do not generally commute; whether a formal Bloch theorem can be rigorously established; and whether hyperbolic band theory can describe finite lattices realized in an experiment. In the present work, we address all three questions simultaneously. By formulating periodic boundary conditions for finite but arbitrarily large lattices, we show that a generalized Bloch theorem can be rigorously proved but may or may not involve higher-dimensional irreducible representations (irreps) of the nonabelian translation group, depending on the lattice geometry. Higher-dimensional irreps correspond to points in a moduli space of higher-rank stable holomorphic vector bundles, which further generalizes the notion of Brillouin zone beyond the Jacobian. For a large class of finite lattices, only 1D irreps appear, and the hyperbolic band theory previously developed becomes exact. [ABSTRACT FROM AUTHOR]

The oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR), and nitrogen reduction reaction (NRR) are important cathodic reactions for renewable fuel production and energy conversion technologies. However, the sluggish kinetics of these reactions hinders the practical applications of the relevant technologies. Perovskite oxides, a promising family of catalysts with great flexibility in composition and structure engineering, exhibit versatility in electrocatalysis of these reactions. In this review, beginning with a brief introduction on the fundamentals of ORR, CO2RR, and NRR, the mechanistic understanding of the electrocatalysis by perovskite oxides is discussed based on both molecular orbital and band theories. The recent advances of perovskite oxide‐based electrocatalysts for ORR, CO2RR, and NRR are then highlighted. Strategies for developing perovskite oxide‐based ORR catalysts are emphasized with representative examples, intending to draw on the experience of developing ORR catalysts to both CO2RR and NRR catalysts. Finally, perspectives on the perovskite oxide‐based electrocatalysis are discussed by paying particular attention to the practical applications and future development of perovskite oxide‐based catalysts. [ABSTRACT FROM AUTHOR]

The oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR), and nitrogen reduction reaction (NRR) are important cathodic reactions for renewable fuel production and energy conversion technologies. However, the sluggish kinetics of these reactions hinders the practical applications of the relevant technologies. Perovskite oxides, a promising family of catalysts with great flexibility in composition and structure engineering, exhibit versatility in electrocatalysis of these reactions. In this review, beginning with a brief introduction on the fundamentals of ORR, CO2RR, and NRR, the mechanistic understanding of the electrocatalysis by perovskite oxides is discussed based on both molecular orbital and band theories. The recent advances of perovskite oxide‐based electrocatalysts for ORR, CO2RR, and NRR are then highlighted. Strategies for developing perovskite oxide‐based ORR catalysts are emphasized with representative examples, intending to draw on the experience of developing ORR catalysts to both CO2RR and NRR catalysts. Finally, perspectives on the perovskite oxide‐based electrocatalysis are discussed by paying particular attention to the practical applications and future development of perovskite oxide‐based catalysts. [ABSTRACT FROM AUTHOR]

Multiple software packages currently exist for the computation of bulk topological invariants in both idealized tight-binding models and realistic Wannier tight-binding models derived from density functional theory. Currently, only one package is capable of computing nested Wilson loops and spin-resolved Wilson loops. These state-of-the-art techniques are vital for accurate analysis of band topology. In this paper we introduce BerryEasy, a python package harnessing the speed of graphical processing units to allow for efficient topological analysis of supercells in the presence of disorder and impurities. Moreover, the BerryEasy package has built-in functionality to accommodate use of realistic many-band tight-binding models derived from first-principles., (Creative Commons Attribution license.)