Masaru SUZUKI (鈴木 勝)

Offer Organization: Japan Society for the Promotion of Science, System Name: Grants-in-Aid for Scientific Research, Category: Grant-in-Aid for Scientific Research (B), Fund Type: -, Overall Grant Amount: - (direct: 5500000, indirect: 1650000)
The compression response characteristics of graphene/C60/graphene interface nanostructures was discussed. First, we focused on the compressive properties of the nanostructure in which a single C60 molecule is sandwiched between graphene sheets. Comparing the effective spring constant of the entire interface system with those of single C60 and of C60-graphene interlayer, it was clarified that the C60/graphene interface system can be regarded as a series spring of C60 single molecule spring and C60-graphene interlayer spring. Next, we focused on the graphene sheet, which is a component of the interface structure, and we developed an effective potential function that coarse-grained the Tersoff potential function, which represents a covalent bond. As a result, we succeeded in increasing the calculation speed of graphene adhesion to 10,000 times that of the conventional Tersoff function.

Offer Organization: Japan Society for the Promotion of Science, System Name: Grants-in-Aid for Scientific Research, Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), Fund Type: -, Overall Grant Amount: - (direct: 29200000, indirect: 8760000)
Elucidation of nanomechanics of π-figurated molecular machine and proposal of precise measurement method have been performed as follows: We developed a model potential suitable for high-speed simulation of friction at the graphene interface, and succeeded in reducing the calculation time to about 1 / 10,000 of the previous one. We proposed a color AFM method to convert tip-surface interaction information into RGB color data and visualize it. We also proposed tribo-phonon spectroscopy (TPS) to detect energy dissipation dynamically using QCM-AFM. The polymer solution containing carbon nanotubes was stretched using a microfluidic device in order to produce a new cell scaffolding material. The compression and friction properties of the sumanene thin film adsorbed on the gold surface were evaluated by molecular dynamics method.

Offer Organization: Japan Society for the Promotion of Science, System Name: Grants-in-Aid for Scientific Research, Category: Grant-in-Aid for Scientific Research (B), Fund Type: -, Overall Grant Amount: - (direct: 3900000, indirect: 1170000)
In order to investigate the influence of graphene curvature on superlubricity, molecular mechanics simulation of peeling process of monolayer graphene sheet adsorbed onto the graphite substrate was carried out. As the initial orientation angle of the graphene adsorption is varied little by little from the AB stacking orientation, the effect of lattice mismatch of the surface contact area appears, and the mean lateral force during the surface contact process markedly decreases to about 0 pN for the orientation angle of 9 deg. For larger orientation angle, the mean lateral force changed only slightly around 0 pN.

Offer Organization: Japan Society for the Promotion of Science, System Name: Grants-in-Aid for Scientific Research, Category: Grant-in-Aid for Scientific Research (B), Fund Type: -, Overall Grant Amount: - (direct: 4300000, indirect: 1290000)
Superlubricity of C60/graphene and graphene/graphene interfaces is studied by molecular mechanics simulation. First, for superlubricity of (graphene)n/C60/(graphene)n interface, difference between multilayer (n>1) and monolayer (n=1) systems are found. For monolayer, superlubricity is derived from only stacking relation between C60 and graphene. However, for multilayer, superlubricity is also derived from that between graphene and graphene, which opens an lower energy path. Next, it is found by theory and experiment that, for peeling and adhesion of graphene sheet, quasiperiodic lateral force curve is obtained due to stick-slip motion during surface contact region, whose period nearly corresponds to the lattice constant of graphite.

Offer Organization: Japan Society for the Promotion of Science, System Name: Grants-in-Aid for Scientific Research, Category: Grant-in-Aid for Scientific Research (B), Fund Type: -, Overall Grant Amount: - (direct: 16500000, indirect: -)
We carried out the researches to establish a basis for manipulating nuclear-spin quantum-coherence of ortho-hydrogen molecule in solid hydrogen. Simultaneously, we developed a method to manipulate optical processes using optical nanofiber ; it was originally proposed to introduce a strong light into the solid hydrogen.
Regarding the ortho-hydrogen project, we developed a highly-stable single-frequency cw laser at 2.4 μm wavelength using doubly-resonant OPO-technique. Ortho-hydrogen infrared transition (v=1-0, J=1-1) was measured systematically. We showed that the transition reveals an ultra-narrow spectral width of 1.6 MHz HWHM. This width is the narrowest width observed just using simple absorption spectroscopy, without using any nonlinear laser-spectroscopic method. Although density of ortho-hydrogen is very low 40 ppm, the peak absorption of 1-cm solid hydrogen crystal reaches to 60% ; it is due to the ultra-narrow spectral feature. We demonstrated also that the vibration-rotation spectrum splits into three components with splittings of about 10 MHz. The origin of the splitting may be understood due to breaking of magnetic degeneracy of J=1 state into three sublevels via crystal field. The observations have demonstrated that the ortho-hydrogen embedded in solid-parahydrogen is a unique system for realizing quantum coherence control in solid. The observed degeneracy breaking may open a new possibility to realize a new Raman three level scheme without magnetic field.
Regarding the nanofiber, we established a method to produce nanofibers with diameter from 1μm to 400 nm with transmission of 80%. We showed theoretically a unique possibility to develop optical processes using nanofibers, very different from those in free space ; a key point is to confine both optical field and atoms/molecules into a submicron space around a nanofiber. We can manipulate single atom/molecule transition just using single photon. Moreover, spontaneous emission of atom/molecule near the nanofiber is strongly modified to emit photons into a guided mode of a nanofiber. We have observed experimentally the unique features of confinement in February of 2006. The observations imply that the nanofiber technique may open a new category of quantum optics.

Offer Organization: Japan Society for the Promotion of Science, System Name: Grants-in-Aid for Scientific Research, Category: Grant-in-Aid for Scientific Research (C), Fund Type: -, Overall Grant Amount: - (direct: 3000000, indirect: -)
In RNi_2B_2C(R=rare earth elements) the superconductivity and the magnetic order of the rare-earth elements coexist, (or compete), where the superconductivity, the magnetism, and the lattice dynamics are closely related to the others. When RE =Ho, the superconducting transition temperature (Tc=7K) is close to the magnetic transition temperature (T_N=5K), and the temperature vs magnetic-field phase diagram for the superconductivity and the magnetism is complicated involving the reentrant superconducting phase and antiferro-, ferri-, ferro-, and incommensurate magnetic phases. The purpose of the present project is to elucidate the interrelation between the superconductivity and the magnetism of HoNi_2B_2C through "lattice" by the ultrasonic measurement and by lattice deformation under uniaxial stresses.
We carefully checked the sample dependence of the superconductivity of the single crystals prepared by a froating-zone infraned furnace, and found that multiple superconducting phases often coexist even in a single crystal.
The Ultrasonic measurements revealed that the elastic constant C_<66>, relevant to the strain along [110], shows a large softening up to 60% with decreasing temperature from 80 K to T_N. We conclude that the strain couples with the ferromagnetic fluctuation of Ho magnetic moments within the c-plane. The elastic constant C_<33>, relevant to the strain along [001], shows a similar softening with decreasing temperature from 80 K to T_N although its change is smaller by two orders of magnitude than C_<66>. In addition, C_<33> shows stepwise softenings associated with the meta-magnetic transitions at 2 K. We conclude that the strain along [001] couples with the magnetic correlation of Ho magnetic moments between the c-planes. We deduced the dependence on the c-spacing of the exchange interactions between the c-planes.
The magnetic measurements under uniaxial stress revealed that T_N increases remarkably by applying a stress along [110]. The rate is larger by 1 order of magnitude than that in the hydro-pressure. On the other hand, T_N dose not change by the stress along [001] within the present precision. We did not find any appreciable change of Tc by the stresses in all directions.
In addition to the above investigation, we performed preliminary x-ray magnetic scattering experiment using synchrotron radiation in Spring-8. We confirmed the periodicity of the antiferro- and ferri- magnetic phases at 2 K by magnetic Bragg scattering.