Spin Polarization and Spin‐Flip Through Phosphorene Superlattice

The spin‐dependent transport properties, including spin polarization and spin‐flip for phosphorene superlattice in the presence of an extrinsic Rashba spin‐orbit interaction (RSOI) based on the transfer matrix method, are studied. The results show that the number of barriers in the superlattice structure plays a dominant role in output spin polarization, which can be used in designing optimized spintronic devices. In addition, by controlling on the Rashba strength, an incident spin‐up electron can be transmitted as a spin‐down electron. Also, it enables to convert the unpolarized incident electronic beam (with zero spin polarization) into an arbitrary output spin polarization, which plays a significant role in qubit circuits.     

Quantum rings as a perfect spin-splitter and spin-filter by using the Rashba effect

Spin related conductance and polarization via an open ballistic quantum nanoringconnected to one input lead and two output ones are studied by considering the Rashbaeffect based on the transfer matrix method. Our probes show that controlling on Rashbastrength leads to 100 percent spin polarization while we have high efficiency for thesystem. In addition, it is possible to design the position of input and output leads insuch a way as to optimize the system to work as a spin filtering or spin switching nanodevice. Also, this apparatus can work as a Stern-Gerlach tool which can be used in someimportant practical nano-industrial applications. By controlling on Rashba strength in aspecial design of two output lead positions, it is possible to divide the input chargecurrent into any output ones while the partial output charge current has substantial valuein one of two output leads and it is reduced in the other one simultaneously. Bycontrolling on Rashba strength in a special design of output lead positions, the spinconductance can attain a considerable value in one output lead despite an insignificantvalue in the other one simultaneously.     

Add/drop filter using in-plane slanted gratings in azo polymers

We have fabricated in-plane slanted gratings on azo-functionalized polymeric films using a fast, direct-writing method. By properly adjusting the resonance, these gratings can be used as 90 degrees integrated reflectors and add/drop filters in the plane of the film. We have produced an attenuation of 14.8 dB at 1560.2 nm with a FWHM of 6.47 nm. Also, a signal of 1548 nm wavelength was added to the output from a different direction. Any light shifted from the resonance will pass through the filter undisturbed.     

Synthesis of novel β-lactams bearing an anthraquinone moiety,and evaluation of their antimalarial activities

A novel series of β-lactams bearing an anthraquinone moiety have been synthesized from imines derived from anthraquinone-2-carbaldehyde and ketenes by a [2+2] cycloaddition reaction. The cycloadducts were fully characterized and evaluated for their antimalarial activities against Plasmodium falciparum K14 resistant strain and showed moderate to excellent EC₅₀ values varying from 9 to 50 μM.     

Disorder-averaged currents in edged topological disordered mesoscopic cylinder

Edged topological disorder in quantum mesoscopic cylinder threaded with magnetic flux is investigated by using exact diagonalization. The Fermi energy continuously varies with respect to magnetic flux against saw-tooth variation in ordered mesoscopic cylinder. In addition, the energy levels repel each other and energy gap appears in variation of energy spectra as a function of magnetic flux in edged topological disordered mesoscopic cylinder rather than ordered ones. In strong edged topological disorder, a narrow mesoscopic cylinder which is a low-dimensional sample behaves in the same way as a three-dimensional system.     

Transport in magnetic graphene superlattice with Rashba spin-orbit interaction

Based on the transfer-matrix method, we have investigated the spin-dependent transport properties of magnetic graphene superlattice in the presence of Rashba spin-orbit interaction (RSOI). It is shown that the angular range of the spin transmission probability through magnetic graphene superlattice can be efficiently controlled by the number of barriers. As the number of magnetic barriers increases, the angular range of the transmission through the magnetic superlattice decreases, the gaps in the transmission and conductivity versus energy become wider. It is also found that the spin conductivities oscillate with the Fermi energy and RSOI strength. Specifically, when a magnetic field is present, the spin polarisation can be observed, whereas for the RSOI alone it is zero. Application of such a phenomenon to design a spin polarised electron device based on the graphene material is anticipated.     

Perfect tuning of spin-polarization in a ring-shaped multiple-quantum-dot nanostructure in the presence of Rashba spin–orbit coupling

Spin-dependent electronic transport through an open multiple-quantum-dot ring threaded by a magnetic flux is theoretically investigated by using the single particle Green?s function method. By introducing local Rashba spin–orbit interaction on an individual quantum dot and local magnetic moments on two of other quantum dots, we calculate the spin-polarization in the output lead. We find the spin-polarization can be tuned by manipulating magnetic moments, adjusting magnetic flux and setting the Rashba spin–orbit strength. It is also shown the system can operate as an efficient spin-inverter when the structure is adjusted properly. The analysis can be utilized in designing optimized nanodevices.     

2-Chloro-1-methylpyridinium iodide,an efficient reagent for the conversion of alcohols into alkyl thiocyanates both under solvent and solvent-free conditions

A new application of the Mukaiyama reagent for the simple phosphine-free conversion of alcohols into the corresponding alkyl thiocyanates is described. This transformation can be achieved either in acetonitrile or under solvent-free conditions and the products obtained in good to excellent yields. The solvent-free procedure described here is the first report on the solvent-free thiocyanation of alcohols.     

Magnetic susceptibility in the edged topological disordered nanoscopic cylinder

The effects of edged topological disorder on magnetic susceptibility are investigated in a nanoscopic cylinder threaded by a magnetic flux. Persistent current versus even or odd number of electrons shows different signs in ordered and disordered cylinders and also in short or long ones. In addition, temperature-averaged susceptibility has only diamagnetic signs in strong regimes and it is associated with paramagnetic signs in ordered and weak disordered ones. Besides, in an edged topological disordered cylinder, the temperature-averaged susceptibility decreases by raising the temperature somewhat and then increasing initiates and finally at high temperature tends to zero as the ordered one.     

Synthesis of mono-, bis-spiro- and dispiro-β-lactams and evaluation of their antimalarial activities

Some new mono-, bis-spiro- and dispiro-β-lactams have been synthesized from imines derived from 9H-fluoren-9-one and a ketene derived from 9H-xanthene-9-carboxylic acid or phenoxyacetic acid by a [2+2] cycloaddition reaction in good to excellent yields varying from 45 to 83%. The biological activity of these monocyclic β-lactams was successfully investigated against Plasmodium falciparum K14 resistant strain with excellent EC₅₀ values up to 5 μM.