Transmission coefficient

About: Transmission coefficient is a research topic. Over the lifetime, 4132 publications have been published within this topic receiving 55320 citations. The topic is also known as: τ & transmission factor.

Single and multiband modeling of quantum electron transport through layered semiconductor devices

Abstract: Non-equilibrium Green function theory is formulated to meet the three main challenges of high bias quantum device modeling: self-consistent charging, incoherent and inelastic scattering, and band structure. The theory is written in a general localized orbital basis using the example of the zinc blende lattice. A Dyson equation treatment of the open system boundaries results in a tunneling formula with a generalized Fisher-Lee form for the transmission coefficient that treats injection from emitter continuum states and emitter quasi-bound states on an equal footing. Scattering is then included. Self-energies which include the effects of polar optical phonons, acoustic phonons, alloy fluctuations, interface roughness, and ionized dopants are derived. Interface roughness is modeled as a layer of alloy in which the cations of a given type cluster into islands. Two different treatments of scattering; self-consistent Born and multiple sequential scattering are formulated, described, and analyzed for numerical t...

Coherence and Phase Sensitive Measurements in a Quantum Dot.

Abstract: Via a novel interference experiment, which measures magnitude and phase of the transmission coefficient through a quantum dot in the Coulomb regime, we prove directly, for the first time, that transport through the dot has a coherent component. We find the same phase of the transmission coefficient at successive Coulomb peaks, each representing a different number of electrons in the dot; however, as we scan through a single Coulomb peak we find an abrupt phase change of \ensuremath{\pi}. The observed behavior of the phase cannot be understood in the single particle framework.

On the transition coordinate for protein folding

Abstract: To understand the kinetics of protein folding, we introduce the concept of a “transition coordinate” which is defined to be the coordinate along which the system progresses most slowly. As a practical implementation of this concept, we define the transmission coefficient for any conformation to be the probability for a chain with the given conformation to fold before it unfolds. Since the transmission coefficient can serve as the best possible measure of kinetic distance for a system, we present two methods by which we can determine how closely any parameter of the system approximates the transmission coefficient. As we determine that the transmission coefficient for a short-chain heteropolymer system is dominated by entropic factors, we have chosen to illustrate the methods mentioned by applying them to geometrical properties of the system such as the number of native contacts and the looplength distribution. We find that these coordinates are not good approximations of the transmission coefficient and therefore, cannot adequately describe the kinetics of protein folding.

Analytic expressions for the electromagnetic mode density in finite, one-dimensional, photonic band-gap structures

Abstract: Summary form only given. We derive an exact expression for the electromagnetic mode density, and hence the group velocity, for a finite N period, one-dimensional photonic band-gap structure. We begin by deriving a general formula for the mode density in terms of the complex transmission coefficient of an arbitrary index profile. Then we develop a formula that gives the N-period mode density in terms of the transmission coefficient of the unit cell. The special cases of mode-density enhancement and suppression at the photonic band edge and at mid gap, respectively are derived. The specific example of a quarter-wave stack is analyzed, and applications to 3D structures, spontaneous emission control, delay lines, band-edge lasers, and superluminal tunneling times are discussed.