Integrated atomistic process and device simulation of decananometre MOSFETs

In this paper we present a methodology for the integrated atomistic process and device simulation of decananometre MOSFETs. The atomistic process simulations were carried out using the kinetic Monte Carlo process simulator DADOS, which is now integrated into the Synopsys 3D process and device simulation suite Taurus. The device simulations were performed using the Glasgow 3D statistical atomistic simulator, which incorporates density gradient quantum corrections. The overall methodology is illustrated in the atomistic process and device simulation of a well behaved 35 nm physical gate length MOSFET reported by Toshiba

(1+1)(1+1) dimensional Dirac equation with non Hermitian interaction

We study $(1+1)$ dimensional Dirac equation with non Hermitian interactions, but real energies. In particular, we analyze the pseudoscalar and scalar interactions in detail, illustrating our observations with some examples. We also show that the relevant hidden symmetry of the Dirac equation with such an interaction is pseudo supersymmetry.Comment: 9 page

Influence of finite volume and magnetic field effects on the QCD phase diagram

The Polyakov linear sigma model (PLSM) is used to investigate the respective influence of a finite volume and a magnetic field on the quark-hadron phase boundary in the plane of baryon chemical potential ($\mu_{B}$) vs. temperature ($T$) of the QCD phase diagram. The calculated results indicate sizable shifts of the quark-hadron phase boundary to lower values of $(\mu_{B}~\text{and}~T)$ for increasing magnetic field strength, and an opposite shift to higher values of $(\mu_{B}~\text{and}~T)$ for decreasing system volume. Such shifts could have important implications for extraction of the thermodynamic properties of the QCD phase diagram from heavy ion data

Electron transport in an open mesoscopic metallic ring

We study electron transport in a normal-metal ring modeled by the tight binding lattice Hamiltonian, coupled to two electron reservoirs. First, Buttiker's model of incorporating inelastic scattering, hence decoherence and dissipation, has been extended by connecting each site of the open ring to one-dimensional leads for uniform dephasing in the ring threaded by magnetic flux. We show with this extension conductance remains symmetric under flux reversal, and Aharonov-Bohm oscillations with changing magnetic flux reduce to zero as a function of the decoherence parameter, thus indicating dephasing in the ring. This extension enables us to find local chemical potential profiles of the ring sites with changing magnetic flux and the decoherence parameter analogously to the four probe measurement. The local electrochemical potential oscillates in the ring sites because of quantum-interference effects. It predicts that measured four-point resistance also fluctuates and even can be negative. Then we point out the role of the closed ring's electronic eigenstates in the persistent current around Fano antiresonances of an asymmetric open ring for both ideal leads and tunnel barriers. Determining the real eigenvalues of the non-Hermitian effective Hamiltonian of the ring, we show that there exist discrete bound states in the continuum of scattering states for the asymmetric ring even in the absence of magnetic flux. Our approach involves quantum Langevin equations and non-equilibrium Green's functions.Comment: 19 pages, 6 figure

Work Fluctuations and Stochastic Resonance

We study Brownian particle motion in a double-well potential driven by an ac force. This system exhibits the phenomenon of stochastic resonance. Distribution of work done on the system over a drive period in the time asymptotic regime have been calculated. We show that fluctuations in the input energy or work done dominate the mean value. The mean value of work done over a period as a function of noise strength can also be used to characterise stochastic resonance in the system. We also discuss the validity of steady state fluctuation theorems in this particular system.Comment: 5 page

NEGF simulations of a junctionless Si gate-all-around nanowire transistor with discrete dopants

We have carried out 3D Non-Equilibrium Green Function simulations of ajunctionlessgate-all-around n-type silicon nanowiretransistor of 4.2 × 4.2 nm2 cross-section. We model the dopants in a fully atomistic way. The dopant distributions are randomly generated following an average doping concentration of 1020 cm−3. Elastic and inelastic phonon scattering is considered in our simulation. Considering the dopants in adiscrete way is the first step in the simulation of random dopant variability in junctionlesstransistors in a fully quantum mechanical way. Our results show that, for devices with an “unlucky” dopants configuration, where there is a starvation of donors under the gate, the threshold voltage can increase by a few hundred mV relative to devices with a more homogeneous distribution of dopants. For the first time we have used a quantum transport model with dissipation to evaluate the change in threshold voltage and subthreshold slope due to the discrete random donors in the channel of ajunctionlessnanowire nMOS transistor. These calculations require a robust convergence scheme between the quantum transport equation and the Poisson equation in order to achieve convergence in the dopant-induced resonance regime

Full-scale thrust reverser testing in an altitude facility

A two-dimensional convergent-divergent exhaust nozzle designed and fabricated by Pratt and Whitney Aircraft was installed on a PW1128 turbofan engine and tested during thrust reverser operation in an altitude facility at NASA Lewis Research Center. A unique collection system was used to capture the thrust reverser exhaust gas and transport it to the primary exhaust collector. Tests were conducted at three flight conditions with varying amounts of thrust reverse at each condition. Some reverser exhaust gas spillage by the collection system was encountered but engine performance was unaffected at all flight conditions tested. Based on the results of this test program, the feasibility of altitude testing of advanced multi-function exhaust nozzle systems has been demonstrated

Contrasting the magnetic response between magnetic-glass and reentrant spin-glass

Magnetic-glass is a recently identified phenomenon in various classes of magnetic systems undergoing a first order magnetic phase transition. We shall highlight here a few experimentally determined characteristics of magnetic-glass and the relevant set of experiments, which will enable to distinguish a magnetic-glass unequivocally from the well known phenomena of spin-glass and reentrant spin-glass.Comment: 10 pages and 4 figures. The preprint has been amended after taking care of various typographical errors, some errors in Figs.2 and 4 and with the addition of some new references. This version has been accepted for publication in Physical Review