A magnetic solid state device is disclosed. The magnetic solid state device includes a substrate and a topological insulator deposited on top of the substrate. The magnetic solid state device also includes a first perpendicular magnetic anisotropy (PMA) bit having a reference PMA layer located on the topological insulator, and a second PMA bit having a free PMA layer located on the topological insulator. A gate contact is utilized to receive various predetermined voltages for controlling the Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions between the reference PMA layer in the first PMA bit and the free PMA layer in the second PMA bit.

Graphical abstract Highlights • We investigated spin polarized electronic transport in buckled bilayer silicene. • No prior study on spin transport in buckled bilayer silicene is conducted. • Spin dephasing length is estimated in range of 2 μm for buckled bilayer silicene. • We observed monotonous variation in spin dephasing length from 4 K to 373 K. • Buckled bilayer silicene is a promising candidate for spintronic devices. Abstract In this article, we have theoretically studied and investigated spin polarized electronic transport in buckled bilayer silicene (BLS) using semi-classical Monte–Carlo approach. Monte Carlo simulations are used to model spin transport along with spin density matrix calculations in the semiconductor devices. Dephasing of the spin vectors in the buckled bilayer silicene is due to Elliott–Yafet (EY) and D’yakonov–Perel (DP) relaxation mechanisms. The spin dephasing length is estimated in the range of 2 μm for buckled bilayer silicene. Next, we investigated the ensemble averaged spin vector variation in buckled bilayer silicene along the length of the device with varying temperature. We observe a negligible variation in the spin dephasing length in the temperature range of 4–77 K. As the temperature increases from 77 K to 373 K, we find a monotonous decrease in the spin dephasing length. In our study, we found buckled bilayer silicene to be a promising candidate for next generation spintronic devices.

We demonstrate the design of a triple gate n-channel junctionless transistor that we call a junctionless tunnel field effect transistor (JLTFET). The JLTFET is a heavily doped junctionless transistor which uses the concept of tunneling, by narrowing the barrier between source and channel of the device, to turn the device ON and OFF. Simulation shows significant improvement compared to simple junctionless field effect transistor both in ION/ IOFF ratio and subthreshold slope. Here, junctionless tunnel field effect transistors with high- k dielectric and low- k spacers are demonstrated through simulation and shows an ON-current of 0.25 mA/mum for the gate voltage of 2 V and an OFF current of 3 pA/mum (neglecting gate leakage). In addition, our device shows optimized performance with high ION/ IOFF (~10 9). Moreover, a subthreshold slope of 47 mV/decade is obtained for a 50 nm gate length of simulated JLTFET at room temperature which indicates that JLTFET is a promising candidate for switching performance.

In this work we perform a study of the data retention behavior of silicon nanocrystalline flash memories. Charge loss is modeled through direct and trap assisted tunneling from the nanocrystals to the channel and to the neighboring nanocrystals. The discrete loss of charge is modeled by a Monte Carlo algorithm. In addition to being more realistic, the Monte Carlo approach, can inherently take into account statistical fluctuations among different memory devices and the effect becomes more important as the devices are scaled down in size. The simulated charge retention data has been fitted to experimental data and show reasonable agreement for various temperatures and oxide thicknesses. [All rights reserved Elsevier].

In this work we perform a study of the data retention behavior of silicon nanocrystalline flash memories. Charge loss is modeled through direct and trap assisted tunneling from the nanocrystals to the channel and to the neighboring nanocrystals. The discrete loss of charge is modeled by a Monte Carlo algorithm. In addition to being more realistic, the Monte Carlo approach, can inherently take into account statistical fluctuations among different memory devices and the effect becomes more important as the devices are scaled down in size. The simulated charge retention data has been fitted to experimental data and show reasonable agreement for various temperatures and oxide thicknesses.

Quantum dot cellular automata (QCA) is a emerging nanotechnology that promises smaller size and lower power consumption, with faster speed compared to the transistor-based technology. In this paper, we have proposed novel 8-into-3 bit simple encoder, 4-into-2 bit priority encoder, scan flip-flop, and pseudo-random bit sequence generator designs in QCA. These circuits are useful components for the design of many logical and functional circuits. Simulation results of the proposed QCA circuits are obtained by using the QCA designer tool. The correctness of the proposed circuits is hence confirmed.

A class of supergravity backgrounds have been proposedas dual descriptions of strong coupling large-N non-commutativeYang-Mills (NCYM) theories in 3+1 dimensions. Howevercalculations of correlation functions in supergravity from anevaluation of relevant classical actions appear ambiguous. Wepropose a resolution of this ambiguity. Assuming that someholographic description exists - regardless of whether it is theNCYM theory - we argue that there should be operators in theholographic boundary theory which create normalized states ofdefinite energy and momenta. An operator version of the dualcorrespondence then provides a calculation of correlators of theseoperators in terms of bulk Green's functions. We show that in thelow-energy limit the correlators reproduce expected answers of theordinary Yang-Mills theory.

We examine the behaviour of Killing spinors on AdS5 under variousdiscrete symmetries of the spacetime. In this way we discover a numberof supersymmetric orbifolds, reproducing the known ones and adding afew novel ones to the list. These orbifolds break the SO(4,2)invariance of AdS5 down to subgroups. We also make some comments on the non-compact Stiefel manifold W4,2.

Abstract In this article we study the effect of external magnetic field and electric field on spin transport in bilayer armchair graphene nanoribbons (GNR) by employing semiclassical Monte Carlo approach. We include D'yakonov-Perel' (DP) relaxation due to structural inversion asymmetry (Rashba spin-orbit coupling) and Elliott-Yafet (EY) relaxation to model spin dephasing. In the model we neglect the effect of local magnetic moments due to adatoms and vacancies. We have considered injection polarization along z -direction perpendicular to the plane of graphene and the magnitude of ensemble averaged spin variation is studied along the x -direction which is the transport direction. To the best of our knowledge there has been no theoretical investigation of the effects of external magnetic field on spin transport in graphene nanoribbons. This theoretical investigation is important in order to identify the factors responsible for experimentally observed spin relaxation length in graphene GNRs. Highlights • We employ Monte Carlo simulation technique to model spin transport in bilayer GNR. • We study effect of external electric and magnetic field on spin relaxation length. • SRL increases with increased width for β- and γ acGNR while it is nearly same for all widths for α –GNR. • SRL decreases in presence of external magnetic field due to the precession and suppression of spin. • SRL decreases with increasing electric field due to increased scattering rate.

In this work we perform full-band Monte Carlo simulations of nanoscale Ge bulk PMOSFETs with ultrathin (<2 nm) effective oxide thickness high-κ dielectrics and investigate the importance of remote Coulomb and remote surface roughness scattering in these devices. In addition to these remote scattering mechanisms, transport is considered in the presence of phonon, ionized impurity, surface roughness scattering and impact ionization. Quantum confinement in the inversion layer is taken into account in the form of a modified potential. We show that the experimentally observed data on the dependence of mobility on the thickness of the high-κ dielectric can be accurately modeled via scattering by remote surface roughness at the gate-dielectric interface and remote Coulomb scattering due to fixed charges in the dielectric. The parameters in the remote scattering mechanisms are fitted by matching Monte Carlo data with those obtained from experiments on the dependence of mobility on the thickness of the dielectric. For a gate overdrive, (Vg − Vt), of 1.0 V, remote scattering mechanisms seem to decrease the saturation current by as much as 15%in these devices. We also show that at the high vertical fields (1 MV/cm) in these experimental devices, remote scattering mechanisms can substantially reduce the mobility for oxide thicknesses below 5 nm.

In this work, we perform a study of spin transport in bilayer graphene using semiclassical Monte Carlo simulation. Both the D鈥檡akonov鈥揚erel鈥?(DP) and Elliot鈥揧afet (EY) mechanisms for spin relaxation are considered. A vertical field of varying magnitude is applied across the bilayer and the dependence of the spin relaxation length on the applied field is considered. It is found that the spin relaxation length is a function of the applied vertical field, due to the effects of the EY and DP mechanisms, and the relaxation length reaches a maximum for a particular value of the vertical field.

In this work, we perform a study of spin transport in bilayer graphene using semiclassical Monte Carlo simulation. Both the D鈥檡akonov鈥揚erel鈥?(DP) and Elliot鈥揧afet (EY) mechanisms for spin relaxation are considered. A vertical field of varying magnitude is applied across the bilayer and the dependence of the spin relaxation length on the applied field is considered. It is found that the spin relaxation length is a function of the applied vertical field, due to the effects of the EY and DP mechanisms, and the relaxation length reaches a maximum for a particular value of the vertical field.