Quantum wires from coupled InAs/GaAs strained quantum dots

The electronic structure of an infinite 1D array of vertically coupled InAs/GaAs strained quantum dots is calculated using an eight-band strain-dependent k-dot-p Hamiltonian. The coupled dots form a unique quantum wire structure in which the miniband widths and effective masses are controlled by the distance between the islands, d. The miniband structure is calculated as a function of d, and it is shown that for d>4 nm the miniband is narrower than the optical phonon energy, while the gap between the first and second minibands is greater than the optical phonon energy. This leads to decreased optical phonon scattering, providing improved quantum wire behavior at high temperatures. These miniband properties are also ideal for Bloch oscillation.Comment: 5 pages revtex, epsf, 8 postscript figure

What Can We Hope For from Law?

What can a lawyer of faith hope for, and expect from, law? This Essay, based on the 2008 Louis Brandeis Lecture given at Pepperdine University, discusses why and how this question matters not just as a matter of theory but to our real-world lawyering journeys. The Essay discusses two of the frameworks that can shape our answer to the question: a natural law viewpoint and what the Essay calls a “Lutheran” view. After explaining how these two perspectives might lead to different expectations about the effects of law, the Essay discusses whether either of these approaches is more sustaining or explanatory over the long run

Peculiar Risk in American Tort Law

American tort law includes a significant strand of liability tied to an intriguing concept variously termed “peculiar risk,” “special danger,” and “special risk inherent in the work,” among others. Peculiar risk presents a basis for liability different from other standards or actions that trigger liability in tort law - it is different from intent, recklessness, negligence, nuisance, and abnormally dangerous activity. Both England and the United States endorsed versions of the doctrine in the late nineteenth and early twentieth centuries. Yet, by 1965, American and English tort law had sharply diverged on the doctrine. American courts continued to apply it; meanwhile, the doctrine had been severely limited in England and rejected in several other common law countries. The divide between the American approach and treatment of the doctrine outside the U.S. is a puzzle. In countries that have rejected or severely limited the doctrine, the critiques have included decisional indeterminacy and shaky historical and normative justifications. Yet a doctrine subject to these criticisms elsewhere has remained well accepted in the United States in the last thirty years - a thirty-year period characterized by extensive tort reform across the bandwidth of tort law. This Article explores three points about this divide between American tort law and the tort law of other common law countries: when and how the divide occurred; why this doctrine - whose breadth and indeterminacy spelled its disfavor elsewhere - remained well-accepted in America despite the intensity and duration of American tort reform; and whether the American version of the doctrine offers lessons for tort law outside the United States

Alien Registration- Pryor, Whitney S. (Monticello, Aroostook County)

https://digitalmaine.com/alien_docs/34048/thumbnail.jp

Eight-band calculations of strained InAs/GaAs quantum dots compared with one, four, and six-band approximations

The electronic structure of pyramidal shaped InAs/GaAs quantum dots is calculated using an eight-band strain dependent $\bf k\cdot p$ Hamiltonian. The influence of strain on band energies and the conduction-band effective mass are examined. Single particle bound-state energies and exciton binding energies are computed as functions of island size. The eight-band results are compared with those for one, four and six bands, and with results from a one-band approximation in which m(r) is determined by the local value of the strain. The eight-band model predicts a lower ground state energy and a larger number of excited states than the other approximations.Comment: 8 pages, 7 figures, revtex, eps

Comparison of two methods for describing the strain profiles in quantum dots

The electronic structure of interfaces between lattice-mismatched semiconductor is sensitive to the strain. We compare two approaches for calculating such inhomogeneous strain -- continuum elasticity (CE, treated as a finite difference problem) and atomistic elasticity (AE). While for small strain the two methods must agree, for the large strains that exist between lattice-mismatched III-V semiconductors (e.g. 7% for InAs/GaAs outside the linearity regime of CE) there are discrepancies. We compare the strain profile obtained by both approaches (including the approximation of the correct C_2 symmetry by the C_4 symmetry in the CE method), when applied to C_2-symmetric InAs pyramidal dots capped by GaAs.Comment: To appear in J. Appl. Physic