座長：金子 竜馬、北井 賢吾
| 氏名： 越智
指導教員名： 千葉 大地 准教授
発表題目（英語）： Strain-induced modulation of magnetic moment in magnetic films deposited on flexible substrates
要旨（英語）： Magnetic films directly deposited on flexible substrates have been used to realize a significant change in magnetic properties through the magnetostriction effect because a large strain can be applied to the ferromagnetic systems by stretching the substrates.
Our group has revealed that a huge magnetic anisotropy modulation can be realized reversibly by applying % order strain to Fe and TbFeCo films deposited on flexible substrates.
On the other hand, it has been reported that magnetic moment of fcc Fe can be modulated by changing its lattice constant and it is consistent with the result of band calculations. Therefore, it is expected that considerable modulation of magnetic moment of fcc Fe might be also possible by using the flexible substrate because the lattice constant is considered to be changed by the large strain.
To realize it, I'm trying to deposit fcc Fe/Cu multilayer films on polyethylene naphthalate (PEN) substrates and investigate the magnetic moment of the system with applying biaxial tensile/compressive strain to it.
| 氏名： 北出
指導教員名： 芦原 聡 准教授
発表題目（英語）： Nonlinear Vibrational Spectroscopy with Plasmonic Nanostructures
要旨（英語）： Infrared (IR) spectroscopy is a powerful tool that provides detailed information about atomic-level structures of molecules and solids. Exploiting the femtosecond IR pulsed laser has enabled nonlinear spectroscopy, such as IR pump-probe spectroscopy and two-dimensional infrared (2DIR) spectroscopy. These techniques bring us enormous information, such as vibrational relaxation, structural dynamics, mode-couplings, and 3D structure.
Infrared spectroscopy techniques can be combined with metallic nanostructures (or plasmonics) to possess enhanced sensitivities and new functions. Plasmonic near-field enhancements amplify the interaction of molecular vibrations with IR light to increase vibrational signals by several orders of magnitude.
Surface phonon polaritons (SPhPs) are electromagnetic surface modes formed by a strong coupling of infrared light and optical phonons in polar crystals. They provide application potential for subwavelength photonics, surface-enhanced spectroscopy, etc. Mode-couplings and dynamic behaviors of surface phonon polaritons, highly relevant to such applications, may be studied with nonlinear infrared spectroscopy with plasmonic enhancement.
In this presentation, I will talk about an outline of IR spectroscopy and plasmonics
and discuss the SPhPs excitation by gold nanostructures.
| 氏名： 柏原 悠
指導教員名： 岩佐 義宏 教授
発表題目（英語）： Conducting interface between insulating transition metal dichalcogenides
要旨（英語）： Electrical conduction at heterointerface between insulators has been widely observed not only in well-known InAs/GaSb heterostructures but also in oxides and organics, providing intriguing playgrounds of various unprecedented physics like helical-edge conduction, two-dimensional superconductivity, and so on. In this presantation, we will report electrical conduction at heterointerfaces between group IV-VI insulating transition-metal dichalcogenides (TMDC).
We fabricated TMDC heterostructures by molecular-beam epitaxy with precise control of each layer thickness, and found that those heterostructures show finite electrical conduction despite the fact that each constituent layer is highly insulating at room temperature, providing new charge-transfer interfaces based on TMDC.
| 氏名： 木村
指導教員名： 志 村 努 教授
発表題目（英語）： Designed plasmonic nanostructures for nonlinear optical force actuated nanomotors
要旨（英語）： When light interact with a material, light momentum transfers to it and it experiences a pressure from the light, which is called optical force. The control of this force makes it possible to manipulate nanoparticles with high-accuracy, so it is applied in various fields such as machinery, chemistry and biophysics. However, there is a few reports of nonlinear optical force, which is caused by a nonlinear optical effect. Using nonlinear optical force, we would manipulate movement of nanoparticles more freely than the linear one, and it is applied to optical driven nanomotors.
Here, we have focused on the second-order nonlinear optical effect of gold nanoparticles. The interaction between light and metal nanoparticles can be enhanced by collective oscillation of free electrons on the metal surface, which is called localized surface plasmon. Designing the shape of the metal at nanoscale can increase the second order nonlinear effect of metal nanoparticles and control the second order radiation from them.
In this presentation, I will talk about the new design of plasmonic nanostructures which can produce unidirectional second order radiation and generate nonlinear optical force in the separation with the linear force.
| 氏名： 菊地
指導教員名： 石坂 香子 准教授
発表題目（英語）： Electronic structures of Ag-intercalated layered transition metal dichalcogenide AgxCrSe2
要旨（英語）： Layered transition metal dichalcogenides (TMDs) exhibit wide variety of electronic structure: metal, semiconductor or isulator. Since TMDs show rich physical properties such as charge density wave, thermoelectricity and so on, they have been studied in considerable researches. Moreover, it is easy to intercalate/deintercalate metal atoms, so metal-intercalated TMDs are also of great interest.
AgCrSe2 is Ag-intercalated chromium selenide. It is known that AgCrSe2 shows order-disorder transition under which location of Ag atom cannot be identified at more than 475 K. The behavior of disordered Ag atoms and ordered CrSe2 layers composes what is called phonon-glass-electron-crystal state for which we can expect useful application of AgCrSe2 for thermoelectric device. To clarify the electronic structure of AgCrSe2, we performed ARPES (Angle-Resolved PhotoEmission Spectroscopy) measurements and it has been revealed that Ag atoms are localized. In the presentation, the electronic structure of AgCrSe2 will be reported in detail.
指導教員名： 樽茶 清悟 教授
発表題目（英語）： Towards electron-spin quantum teleportation in a triple quantum dot
要旨（英語）： Electron-spin system in semiconductor quantum dots is a promising architecture for quantum computing. For quantum information processing, it is an important step to achieve simple algorithms. Quantum teleportation (QT) is a good milestone because it can be realized by a triple quantum dot and is realized by qubits using other physical systems.
Coherence of quantum-dot-based spin qubits, however, is lost easily because spin is exposed to the fluctuating hyperfine field in the host material, which shifts the resonance frequency of a quantum dot. Here, we design an experimental scheme of QT partially and calculate the influence of the fluctuation on fidelity of teleportation by numerical simulation in order to estimate the limit of the shift of resonance frequencies.