Magnetic impurities in graphane with dehydrogenated channels

Abstract

We have investigated the electronic and magnetic response of a single Fe atom and a pair of interacting Fe atoms placed in patterned dehydrogenated channels in graphane within the framework of density functional theory. We have considered two channels: "armchair" and "zigzag" channels. Fully relaxed calculations have been carried out for three different channel widths. Our calculations reveal that the response to the magnetic impurities is very different for these two channels. We have also shown that one can stabilize magnetic impurities (Fe in the present case) along the channels of bare carbon atoms, giving rise to a magnetic insulator or a spin gapless semiconductor. Our calculations with spin-orbit coupling shows a large in-plane magnetic anisotropy energy for the case of the armchair channel. The magnetic exchange coupling between two Fe atoms placed in the semiconducting channel with an armchair edge is very weakly ferromagnetic whereas a fairly strong ferromagnetic coupling is observed for reasonable separations between Fe atoms in the zigzag-edged metallic channel with the coupling mediated by the bare carbon atoms. The possibility of realizing an ultrathin device with interesting magnetic properties is discussed

Controlled transportation of mesoscopic particles by enhanced spin-orbit interaction of light in an optical trap

“…The intensity distribution near the focal plane in this case, as imaged and also theoretically derived in Ref. [12]), resembles a ring structure where beads could be trapped. In the current study, we make use of the azimuthal asymmetry in this intensity distribution and its polarization dependence caused by enhanced SOI in our system to trap single asymmetric particles and transport them controllably along the ring.…”

“…Recently, we demonstrated self assembled closed ring structures of micron-sized polystyrene beads in our trap using such a stratified medium [12]. The intensity distribution near the focal plane in this case, as imaged and also theoretically derived in Ref.…”

“…As shown in Fig. 2, we are able to transport pea-pods over ring diameters between 2 -5 µm corresponding to periphery lengths of 6 -15 µm by varying the z-focus of the trapping microscope [12]. A time series plot showing four CCD images taken of a pea-pod trapped in the ring and then translated along the periphery by varying the polarization angle is shown in Fig.…”

“…The sample thickness is 20 µm, and the geometrical beam focus is at an axial distance of 13 µm inside the chamber. Note that the actual focus gets shifted to around 18 µm for the RI-mismatched case due to the effect of the stratified medium [12], so that the input beam focuses very close to the top slide. Also, the off-axis (x = 1.3 µm) value of D for the RImismatched cover slips is about 25 times higher than the corresponding value for the RI-matched ones, indicating significantly enhanced SOI.…”

Controlling Electronic Structure and Transport Properties of Zigzag Graphene Nanoribbons by Edge Functionalization with Fluorine

“…Chemical functionalization of bulk graphene by H and F has been regarded as a suitable route to achieve this effect. [4][5][6][7][8][9] The other prominent route is to consider nanoribbons with various types of edge functionalization by light elements (H, F, Cl, O etc.) 10,11 or organic molecules.…”