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Full-Text Articles in Physics

A Long-Channel Model For The Asymmetric Double-Gate Mosfet Valid In All Regions Of Operation, Abhishek Kammula, Bradley Minch Jul 2012

A Long-Channel Model For The Asymmetric Double-Gate Mosfet Valid In All Regions Of Operation, Abhishek Kammula, Bradley Minch

Bradley Minch

We present a physically based, continuous analytical model for long-channel double-gate MOSFETs. The model is particularly well suited for implementation in circuit simulators due to the simple expressions for the current andthe continuous nature of the derivatives of the current which improves convergence behavior.


Multiple-Scattering Theory Of Itinerant Electron Magnetism In Random Muffin-Tin Alloys, S. Kaprzyk, A. Bansil Apr 2012

Multiple-Scattering Theory Of Itinerant Electron Magnetism In Random Muffin-Tin Alloys, S. Kaprzyk, A. Bansil

Arun Bansil

We discuss the equilibrium electronic structure of a random binary alloy within the framework of a spin-dependent muffin-tin Hamiltonian. The disorder is treated on the basis of the single-site approximations (SSA), especially the average t-matrix and the coherent potential approximations. The local-spin-density (LSD) functional approach is employed to relate the electron and the spin densities with the atomic potentials, thus providing a fully self-consistent description of the ground-state properties of the random alloy. By using the atomic magnetic moments as expansion parameters, a Stoner-type linearized form of the full SSA-LSD formalism is developed. This analysis yields insights into the nature …


Modeling Free-Carrier Absorption And Avalanching By Ultrashort Laser Pulses, Jeremy Gulley Aug 2011

Modeling Free-Carrier Absorption And Avalanching By Ultrashort Laser Pulses, Jeremy Gulley

Jeremy R. Gulley

In the past decade it was demonstrated experimentally that negatively-chirped laser pulses can lower the surface LIDT for wide band-gap materials by decreasing the number of photons required for photoionization on the leading edge of the pulse. Similarly, simulations have shown that positively-chirped pulses resulting from selffocusing and self-phase modulation in bulk dielectrics can alter the onset of laser-induced material modifications by increasing the number of photons required for photoionization on the leading edge of the pulse. However, the role of multi-chromatic effects in free-carrier absorption and avalanching has yet to be addressed. In this work a frequency-selective model of …


Simulation And Analysis Of Ultrafast Laser Pulse Induced Plasma Generation In Dielectric Materials, Jeremy Gulley, Sebastian Winkler, William Dennis Mar 2007

Simulation And Analysis Of Ultrafast Laser Pulse Induced Plasma Generation In Dielectric Materials, Jeremy Gulley, Sebastian Winkler, William Dennis

Jeremy R. Gulley

Recent experiments on optical damage by ultrashort laser pulses have demonstrated that the temporal pulseshape can dramatically influence plasma generation in fused silica and sapphire. In this work a modified 3+1D nonlinear Schroedinger equation for the pulse propagation coupled to a rate equation for the plasma density in the dielectric material is used to simulate pulse propagation and plasma formation in a range of dielectric materials. We use these simulations to analyze the influence of pulse-width, pulse-shape and beam geometry on the formation of the electron plasma and hence damage in the bulk material. In particular, when possible, we simulate …