J. H. Davies

Cardiff University

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D. Rhodri Davies

Australian National University

James Panton

Cardiff University

Asen Asenov

University of Glasgow

A. R. Brown

École Polytechnique Fédérale de Lausanne

I. A. Larkin

Institute of Microelectronics Technology and High Purity Materials

John W. Wilkins

Uniformed Services University of the Health Sciences

M. Holland

Taiwan Semiconductor Manufacturing Company (Taiwan)

Matthew Price

Cardiff University

G. Slavcheva

University of Graz

Martin Wolstencroft

Cardiff University

Cooperative Institutions

University of Glasgow

University of Bristol

Cardiff University

University of Oxford

Imperial College London

Bristol Robotics Laboratory

University of Cambridge

University College London

Lancaster University

Massachusetts Institute of Technology

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CXXIV. Nuclear transmutations produced by cosmic-ray particles of great energy.—Part VI. Experimental results on meson production

The London Edinburgh and Dublin Philosophical Magazine and Journal of Science (1951)

U. Camerini J. H. Davies P. H. Fowler C. Franzinetti H. Muirhead

Summary An analysis has been made of the secondary particles ejected from nuclear disintegrations observed in electron sensitive emulsions exposed to the cosmic radiation at 68,000 ft. Scattering and grain density measure-ments have been carried out on the tracks of 2000 particles associated with these stars. In addition, the grain density and angular distribution of 3070 shower particles and 1508 “grey” tracks have been measured. For 200 stars, the energy of the primary particle which produced the disintegration was measured. A detailed analysis was made of such events. Single fast τ-mesons of kinetic energy less than 1 BeV. are found to interact strongly with nuclear matter. An estimate of the frequency of occurrence of neutral mesons was made from a consideration of the energy balance in stars of low multiplicity, n s .

Multiplicity (mathematics)

10.1080/14786444108561381

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Citations (96)

Time Dependent Layering in Earth's Mantle: Mantle Avalanches and Thermal Pulses

AGU Fall Meeting Abstracts (2008)

Martin Wolstencroft J. H. Davies

Layering

Source

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Geodynamic control on melting in 3D mantle convection models

Goldschmidt Abstracts (2023)

Nicolas Récalde D. Porcelli Morten B. Andersen J. H. Davies James Panton

geodynamics

10.7185/gold2023.14970

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Quantum dots induced by strain from buried and surface stressors

Applied Physics Letters (1999)

J. H. Davies

Quantum dots can be induced in a quantum well by strain from a buried, self-assembled dot or from a stressor on the surface. The elastic fields are shown to be significantly different in their ability to trap carriers. There is no dilation around a buried dot, which therefore has no effect on electrons, and the axial strain repels both holes and excitons. A stressor on the surface, in contrast, produces dilation that can confine all carriers. In both cases, the piezoelectric potential may trap electrons and holes separately in space, storing long-lived spatially indirect excitons.

Strain (injury)

10.1063/1.125563

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Citations (41)

Modal analysis of transport through quantum point contacts using realistic potentials

Physical review. B, Condensed matter (1991)

Michael John Laughton John R. Barker John A. Nixon J. H. Davies

We have studied conduction through quantum point contacts using a coupled-mode analysis and realistic potentials. Disorder causes transport to be strongly nonadiabatic with rapid intermode scattering. The conductance can remain well quantized because of the predominantly forward nature of the scattering. Resonances in the channel lead to strong indirect backscattering that cannot be described by the Born approximation. This degrades quantization in point contacts and reduces the mobility of narrow wires.

Quantum wire

Born approximation

10.1103/physrevb.44.1150

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Citations (55)

Comment on 'Temperature dependence of electrical conductivity and the probability density function' by P. Love

Journal of Physics C Solid State Physics (1984)

J. H. Davies

For original paper see Love ibid., vol.16, p.5985 (1983). The arguments used in a recent paper to derive a formula for the electrical conductivity involving the derivative of the Fermi occupation function with respect to temperature are shown to be wrong.

Derivative (finance)

10.1088/0022-3719/17/22/005

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Citations (2)

Tomographic imaging of multiple mantle plumes in the uppermost lower mantle

Geophysical Journal International (2001)

Mark Rhodes J. H. Davies

A high-resolution global tomographic inversion of P-wave traveltimes has been undertaken utilizing an a priori model. The results image cylindrical slow velocities in the upper and lower mantle beneath many current hotspot locations. Locations at which such plume-like features are imaged passing from the uppermost lower mantle to the upper mantle include, Afar, Society Islands, Crozet, Kerguelen, Iceland, Hawaii, East Africa, Cape Verde and the Canary Islands. The validity of these images has been investigated with synthetic recovery tests. These images suggest that these plumes could be from the lower mantle and therefore are not hindered in crossing the upper/lower mantle boundary.

Hotspot (geology)

Cape verde

Mantle plume

Seismic Tomography

10.1046/j.0956-540x.2001.01512.x

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Citations (25)

HETEROSTRUCTURES

Cambridge University Press eBooks (1997)

J. H. Davies

This chapter provides a review of the general properties of heterostructures, semiconductors composed of more than one material. Variations in composition are used to control the motion of electrons and holes through band engineering. Knowledge of the alignment of bands at a heterojunction, where two materials meet, is essential but has proved difficult to determine even for the best-studied junction, GaAs–AlxGa1−xAs. Although effort was initially concentrated on materials of nearly identical lattice constant, current applications require properties that can be met only by mismatched materials, giving strained layers.

Lattice constant

10.1017/cbo9780511819070.005

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The mobility edge in amorphous silicon

Philosophical Magazine B (1980)

J. H. Davies

Abstract The calculations of this paper are an attempt to find out whether the range of localized states, ΔE = 0.2 eV, observed in amorphous silicon prepared by glow-discharge decomposition of silane is a property inherent in the silicon, or is a result of the considerable amount of hydrogen incorporated into the material. A simple model is presented which gives a value of ΔE of the observed magnitude for a continuous random network of pure silicon. It is argued that the p-like content of the wavefunctions is imporant for obtaining such a large value of ΔE and that the main source of disorder is the random orientation of the tetrahedra. Calculating the scattering due to this, a mean free path for a conduction-band electron is derived. This is used to fix the amount of disorder in an equivalent Anderson model on the same lattice, from which ΔE may be found using the analysis of Abou-Chacra and Thouless (1974). This is found to give a range of localized states about 0.28 eV wide. Using the same model, the effect of hydrogen is found to be small, a 10% concentration increasing the value of ΔE only by 0.02 eV or less.

Lattice (music)

Tetrahedron

10.1080/13642818008245394

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Citations (10)

Dynamic Earth — Plates, Plumes and Mantle Convection

Tectonophysics (2001)

J. H. Davies

Mantle plume

10.1016/s0040-1951(01)00067-1

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Citations (95)