Y. Niimi

Indication of intrinsic spin Hall effect in 4d and 5d transition metals

We have investigated spin Hall effects in 4

Analysis of the reactivity and selectivity of fullerene dimerization reactions at the atomic level

d

Extrinsic spin Hall effect induced by iridium impurities in copper.

and 5

Heterogeneous nucleation of organic crystals mediated by single-molecule templates.

d

Electron Microscopic Imaging of a Single Group 8 Metal Atom Catalyzing C–C Bond Reorganization of Fullerenes

transition metals, Nb, Ta, Mo, Pd and Pt, by incorporating the spin absorption method in the lateral spin valve structure; where large spin current preferably relaxes into the transition metals, exhibiting strong spin-orbit interactions. Thereby nonlocal spin valve measurements enable us to evaluate their spin Hall conductivities. The sign of the spin Hall conductivity changes systematically depending on the number of

Real-space imaging of alternate localization and extension of quasi-two-dimensional electronic states at graphite surfaces in magnetic fields

d

Quasiparticle-mediated spin Hall effect in a superconductor

electrons. This tendency is in good agreement with the recent theoretical calculation based on the intrinsic spin Hall effect.

Imaging of Conformational Changes of Biotinylated Triamide Molecules Covalently Bonded to a Carbon Nanotube Surface

High-resolution transmission electron microscopy has proved useful for its ability to provide time-resolved images of small molecules and their movements. One of the next challenges in this area is to visualize chemical reactions by monitoring time-dependent changes in the atomic positions of reacting molecules. Such images may provide information that is not available with other experimental methods. Here we report a study on bimolecular reactions of fullerene and metallofullerene molecules inside carbon nanotubes as a function of electron dose. Images of how the fullerenes move during the dimerization process reveal the specific orientations in which two molecules interact, as well as how bond reorganization occurs after their initial contact. Studies on the concentration, specimen temperature, effect of catalyst and accelerating voltage indicate that the reactions can be imaged under a variety of conditions.

Construction of a versatile ultralow temperature scanning tunneling microscope

We study the extrinsic spin Hall effect induced by Ir impurities in Cu by injecting a pure spin current into a CuIr wire from a lateral spin valve structure. While no spin Hall effect is observed without Ir impurity, the spin Hall resistivity of CuIr increases linearly with the impurity concentration. The spin Hall angle of CuIr, (2.1±0.6)% throughout the concentration range between 1% and 12%, is practically independent of temperature. These results represent a clear example of predominant skew scattering extrinsic contribution to the spin Hall effect in a nonmagnetic alloy.

Localized distributions of quasi-two-dimensional electronic states near defects artificially created at graphite surfaces in magnetic fields.

Fundamental understanding of how crystals of organic molecules nucleate on a surface remains limited because of the difficulty of probing rare events at the molecular scale. Here we show that single-molecule templates on the surface of carbon nanohorns can nucleate the crystallization of two organic compounds from a supersaturated solution by mediating the formation of disordered and mobile molecular nanoclusters on the templates. Single-molecule real-time transmission electron microscopy indicates that each nanocluster consists of a maximum of approximately 15 molecules, that there are fewer nanoclusters than crystals in solution, and that in the absence of templates physisorption, but not crystal formation, occurs. Our findings suggest that template-induced heterogeneous nucleation mechanistically resembles two-step homogeneous nucleation.