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There was no ‘One, two, three, and away’, but they began running when they liked and left off when they liked, so that it was not easy to know when the race was over. Of all technological accomplishments, none so epitomizes human skill and ingenuity as the harnessing of electricity. Because so much of modern existence is based on it, electrical energy is inevitably taken for granted. Only occasional power failures are capable of reminding us just how dependent we are on this invisible commodity. The practical use of electricity is a surprisingly recent development. It is hard to believe that many of the scientists who precipitated this revolution, made their discoveries as recently as in the nineteenth century, and frequently wrote up their laboratory notes by candle-light. The great advances in atomic physics, early in the twentieth century, paved the way for a second revolution: solid state electronics. Its impact on society has been enormous, giving rise to new industries, new professions, new communication techniques and new organizations. Both revolutions depended, to an exceptional degree, on progress in fundamental science. The people responsible for this breathtaking series of innovations were primarily concerned with abstract ideas, but their efforts have given society radio, television, the telephone, the computer, new forms of heating, lighting, power and transport, and a host of other developments. Many electrical phenomena are transient in nature, whereas magnetism has the advantage of relative permanence. [ABSTRACT FROM AUTHOR]

All that is, at all, Lasts ever, past recall, Earth changes, But thy soul and God stand sure, Time's wheel runs back or stops: Potter and clay endure. Of all the different types of material, ceramics might be the most difficult to define. Many would regard them as falling in a small and rather restricted group, and the only examples that come readily to mind would probably be bathroom fixtures, tiles, and the insulators in spark plugs and on telephone poles. The term ceramic actually covers a large variety of natural and artificial substances that share the desirable qualities of hardness and resistance to heat, electricity and corrosion. Just how large and how important the ceramic domain is can be gauged by some of its members: stone, brick, concrete, sand, diamond, glass, clay and quartz. If there has been a lack of understanding of ceramics, it is excusable because even dictionary definitions tend to be rather narrow. We find them restricted to either pottery or porcelain in most cases, and even the better efforts usually go no farther than ‘products of industries involving the use of clay or other silicates’. The word ceramic actually comes from the Greek word keramos, which means burnt stuff. This is too broad a term to be useful here. The best working definition uses a combination of chemical and physical criteria. [ABSTRACT FROM AUTHOR]

Where order in variety we see, and where, though all things differ, all agree. The development of the modern atomic theory of matter owes much to the more venerable science of crystallography. One of the major clues leading to the discovery of the periodic table was the recognition that the elements are divided into groups having a family likeness. This derived, in part, from the appearance of crystals containing the elements in question. Crystallography was established during a remarkably fruitful decade around the late 1660s. Studying the shapes of crystals of alum, which is potassium aluminium sulphate, and possibly comparing them with orderly piles of musket shot or cannon-balls, Robert Hooke concluded that a crystal must owe its regular shape to the systematic packing of minute spherical particles. A few years later, in 1669, Niels Steensen, also known by the name Nicolaus Steno, noticed that the angles between equivalent pairs of faces of quartz crystals are always the same. Subsequent studies revealed that the same is true of other crystals, even though their shapes are different from that of quartz. Around 1690, Christiaan Huygens succeeded in explaining the three-dimensional structure of crystals of Iceland spar, or calcite, on the basis of regular stacking of equal spheroids. These solid figures are generated by rotating an ellipse about one of its axes. The next significant advance came in 1781. [ABSTRACT FROM AUTHOR]

A brief review is given on the electronic and optical properties of carbon nanotubes with emphasis on Aharonov-Bohm effects. The topics include an effective-mass description of the electronic states, optical absorption and excitons, their fine structure, optical absorption for perpendicular polarization, and optical phonons. [ABSTRACT FROM AUTHOR]

In this chapter, elastic continuum models are used to describe phonons in carbon nanotubes and vibrational modes in biological structures. Based on elastic continuum theory, acoustic vibrational modes are modeled for both zigzag and armchair nanotubes of finite length using a variational solution of Donnell's equation. The acoustic phonon modes in these calculations are determined for both even and odd modes of the acoustic displacement. The dispersion relations vary with the length of the tube. The displacement field of the nanotube is used to calculate the deformation potential interaction Hamiltonian. In addition, the optical vibrational modes are derived for finite length nanotubes in the elastic continuum approximation. A quantum mechanical normalization prescription is applied to facilitate the determination of the optical phonon modes. The dispersion relation is calculated based on the continuum approach and the quantum normalized amplitude is used to calculate the optical deformation potential. These fully three-dimensional elastic continuum models are compared with other approaches to modeling phonons in carbon nanotubes such as the popular zone-folding technique. In a related underlying topic, the applicability of continuum models for the analysis of nanoscale structures is demonstrated for the case fullerenes. It is shown that the b2 elongation mode of C60 may be described within the continuum approximation. Indeed, for these fullerene structures, the frequencies of selected vibrational modes are predicted to within a few percent. [ABSTRACT FROM AUTHOR]

In this chapter we have discussed the transport of charges in semiconductors under the influence of external fields. We have used the effective mass approximation to treat the free carriers as having classical charge and renormalized masses. We first considered the case of weak fields in which the field does not distort the carrier distribution but causes the entire distribution to move with a drift velocity. The drift velocity is determined by the length of time, known as the scattering time, over which the carriers can accelerate in the field before they are scattered. We also defined mobility as the constant of proportionality between drift velocity and electric field. We calculated the scattering rates for carriers scattered by acoustic phonons, optical phonons, and ionized impurities. Using these scattering rates we deduced the temperature dependence of the carrier mobilities. Based on this temperature dependence we introduced modulation doping as a way to minimize scattering by ionized impurities at low temperatures. We discussed qualitatively the behavior of carriers under high electric fields. We showed that these hot carriers do not obey Ohm’s law. Instead, their drift velocities at high fields saturate at a constant value known as the saturation velocity. We showed that the saturation velocity is about 107 cm/s in most semiconductors as a result of energy and momentum relaxation of carriers by scattering with optical phonons. In a few n-type semiconductors, such as GaAs, the drift velocity can overshoot the saturation velocity and exhibit negative differential resistance. This is the result of these semiconductors having secondary conduction band valleys whose energies are of the order of 0.1 eV above the lowest conduction band minimum. The existence of negative differential resistance leads to spontaneous current oscillations at microwave frequencies when thin samples are subjected to high electric fields, a phenomenon known as the Gunn effect. Under the combined influence of an electric and magnetic field, the transport of carriers in a semiconductor is described by an antisymmetric second rank magneto-conductivity tensor. One important application of this tensor is in explaining the Hall effect. The Hall coefficient provides the most direct way to determine the sign and concentration of charged carriers in a sample. [ABSTRACT FROM AUTHOR]

The article focuses on hot carriers which are charged carriers in semiconductor materials that have a higher energy than they have when in thermal equilibrium with the host material's lattice temperature. Both hot electrons and hot holes can exist. The energy of hot carriers can be ten to a few hundred times higher than that of thermal equilibrium. In thermal equilibrium at normal semiconductor device operating temperatures, the equilibrium is maintained by continuous exchange of energy between the carriers and the lattice via phonons.

This panel was intended to function as a discussion, but instead it emerged as a series of short presentations by the participants Robert Brout, Tian Yu Cao, and Peter Higgs, with an introductory discussion by the chair. The present chapter consists of a revised and edited version of those reports and also includes a later submission by Yoichiro Nambu, who was scheduled to be on the panel originally but was unable to attend. Introduction The two sectors of the current Standard Model of particle physics, the strong color and the electroweak sectors, are distinct and are tied together only by ontology. Together, they describe the interactions, other than gravitation, of the three generations of quarks and leptons. The dream of representing the strong and weak “nuclear” interactions (as they were known before the acceptance of the quarks) as quantum field theories (QFT) goes back to the 1930s. The first such QFT, other than quantum electrodynamics, was Enrico Fermi's weak-interaction theory of 1934. This theory was almost immediately extended by Werner Heisenberg in 1935 to include the strong interactions (thus making it the first unified QFT) whose exchanged “quanta” were those of the electron-neutrino “Fermi-field.” In 1935, Hideki Yukawa invented “U-quanta,” now called pions, to represent the field of strong interactions, adjusting their mass to fit the range of nuclear forces. This was again a unified QFT, as the U-quanta were also intended to serve as intermediate bosons of the weak interaction. [ABSTRACT FROM AUTHOR]