Fuse-holder concept expedites electronic component changes

Mounting circuit components in fuse holders facilitates component changing and extends component life with an estimated fifty percent saving of breadboard test time. Glass sleeves of the fuse holders allow easy component identification

Disentangling lattice and electronic contributions to the metal–insulator transition from bulk vs. layer confined RNiO₃

In complex oxide materials, changes in electronic properties are often associated with changes in crystal structure, raising the question of the relative roles of the electronic and lattice effects in driving the metal–insulator transition. This paper presents a combined theoretical and experimental analysis of the dependence of the metal–insulator transition of NdNiO3 on crystal structure, specifically comparing properties of bulk materials to 1- and 2-layer samples of NdNiO3 grown between multiple electronically inert NdAlO3 counterlayers in a superlattice. The comparison amplifies and validates a theoretical approach developed in previous papers and disentangles the electronic and lattice contributions, through an independent variation of each. In bulk NdNiO3, the correlations are not strong enough to drive a metal–insulator transition by themselves: A lattice distortion is required. Ultrathin films exhibit 2 additional electronic effects and 1 lattice-related effect. The electronic effects are quantum confinement, leading to dimensional reduction of the electronic Hamiltonian and an increase in electronic bandwidth due to counterlayer-induced bond-angle changes. We find that the confinement effect is much more important. The lattice effect is an increase in stiffness due to the cost of propagation of the lattice disproportionation into the confining material

Nearsightedness of Electronic Matter in One Dimension

The concept of nearsightedeness of electronic matter (NEM) was introduced by W. Kohn in 1996 as the physical principal underlining Yang's electronic structure alghoritm of divide and conquer. It describes the fact that, for fixed chemical potential, local electronic properties at a point $r$, like the density $n(r)$, depend significantly on the external potential $v$ only at nearby points. Changes $\Delta v$ of that potential, {\it no matter how large}, beyond a distance $\textsf{R}$, have {\it limited} effects on local electronic properties, which tend to zero as function of $\textsf{R}$. This remains true even if the changes in the external potential completely surrounds the point $r$. NEM can be quantitatively characterized by the nearsightedness range, $\textsf{\textsf{R}}(r,\Delta n)$, defined as the smallest distance from $r$, beyond which {\it any} change of the external potential produces a density change, at $r$, smaller than a given $\Delta n$. The present paper gives a detailed analysis of NEM for periodic metals and insulators in 1D and includes sharp, explicit estimates of the nearsightedness range. Since NEM involves arbitrary changes of the external potential, strong, even qualitative changes can occur in the system, such as the discretization of energy bands or the complete filling of the insulating gap of an insulator with continuum spectrum. In spite of such drastic changes, we show that $\Delta v$ has only a limited effect on the density, which can be quantified in terms of simple parameters of the unperturbed system.Comment: 10 pages, 9 figure

Electronically Manufactured Law

This Article seeks to strengthen the case for the academy and the legal profession to pay heed to the consequences of the shift to electronic research, primarily by employing cognitive psychology to guide predictions about the impacts of the shift and, thereby, address a perceived credibility gap. This credibility gap arises from the difficulty and imprecision in postulating how changes in the research process translate into changes in researcher behavior and research outcomes. Applying principles of cognitive psychology to compare the print and electronic research processes provides an analytical basis for connecting changes in the research process with changes in researcher behavior and research outcomes. Cognitive psychology generates two specific predictions about how electronic research will change the law. First, electronic research will lead to increased diversity in framing -- divergence in the selection of the legal theory or theories through which to conceptualize facts, arguments, and cases. Second, electronic research will lead to more tilting at windmills -- the advancement of marginal cases, theories, and arguments. The Article explores how an increase in diversity in framing and tilting at windmills could affect the legal profession and the law. For example, in an adversarial system, judicial options for case resolution are largely defined and constrained by the theories proffered by counsel. Diversity in framing could expand judicial authority by providing judges with a wider variety of options for dispute resolution. This underlines the way in which counsel serve as gatekeepers by exercising judgment about which cases and theories have sufficient merit to warrant pursuit. Increased tilting at windmills may require recalibration of the existing limits placed on lawyers in their role as gatekeepers. Recalibration may be necessary to prevent the dedication of client and judicial resources to lost causes spurred by lapses in judgment related to electronic research and to allow attorneys to advance, without fear of sanctions, thoughtful arguments designed to push doctrinal boundaries. Specifically, Part II reviews existing legal theory, scholarship, and data that suggest that the shift to electronic research will likely have broad-ranging impacts. Part III compares print and electronic research and discusses three particularly salient changes in research process: (1) electronic researchers are not guided by the key system to the same extent as print researchers when identifying relevant theories, principles, and cases; (2) electronic researchers do not encounter and interpret individual cases through the lens of key system information to the same extent as print researchers; and (3) electronic researchers are exposed to more and different case texts than print researchers. Part IV uses principles of cognitive psychology to examine these process differences and predict two major non-process consequences of the shift to electronic research: increased diversity in framing and tilting at windmills. Part V concludes by assessing the broader significance of these hypothesized consequences

Picosecond electric-field-induced threshold switching in phase-change materials

Many chalcogenide glasses undergo a breakdown in electronic resistance above a critical field strength. Known as threshold switching, this mechanism enables field-induced crystallization in emerging phase-change memory. Purely electronic as well as crystal nucleation assisted models have been employed to explain the electronic breakdown. Here, picosecond electric pulses are used to excite amorphous Ag$_4$In$_3$Sb$_{67}$Te$_{26}$. Field-dependent reversible changes in conductivity and pulse-driven crystallization are observed. The present results show that threshold switching can take place within the electric pulse on sub-picosecond time-scales - faster than crystals can nucleate. This supports purely electronic models of threshold switching and reveals potential applications as an ultrafast electronic switch.Comment: 6 pages manuscript with 3 figures and 8 pages supplementary materia

Electrochemical doping of few layer ZrNCl from first-principles: electronic and structural properties in field-effect configuration

We develop a first-principles theoretical approach to doping in field-effect devices. The method allows for calculation of the electronic structure as well as complete structural relaxation in field-effect configuration using density-functional theory. We apply our approach to ionic-liquid-based field-effect doping of monolayer, bilayer, and trilayer ZrNCl and analyze in detail the structural changes induced by the electric field. We show that, contrary to what is assumed in previous experimental works, only one ZrNCl layer is electrochemically doped and that this induces large structural changes within the layer. Surprisingly, despite these structural and electronic changes, the density of states at the Fermi energy is independent of the doping. Our findings imply a substantial revision of the phase diagram of electrochemically doped ZrNCl and elucidate crucial differences with superconductivity in Li intercalated bulk ZrNCl.Comment: 15 pages, 14 figure

Percolative Model for Nanoscale Phase Separation in High Temperature Superconductors

The nature of the phase diagrams of HTSC is clarified by discussing two kinds of phase diagrams, that of the host crystalline lattice, and that of the dopant glass. The latter is associated with changes in the electronic properties, while the former is much more accessible to direct experimental identification, by diffraction, of nanoscale phase separation. Careful examination of electronic properties in both the normal and superconductive states reveals that there are several electronic miscibility gaps in YBa2Cu3Ox and La2-xSrxCuO4 that have been previously overlooked. Recent experiments on the pseudogap in Bi2Sr1.6La0.4CuOy also reveal an electronic miscibility gap.Comment: 10 pages, 3 figure