座長： 諏訪 貴洋、林 洋平
| 氏名： 平川
指導教員名： 長谷川 達生 教授
発表題目（英語）： Dispersion Stability and Effect of Dispersion-Media Composition in Silver Nanocolloids as Dedicated for Ultrafine Silver-Pattern Printing
要旨（英語）： Silver nanocolloid is an important material for printing-based device production technologies (i.e. printed electronics). Recently, we have developed a new printing technique to manufacture ultrafine conductive patterns by using weakly encapsulated silver nanoparticles densely suspended in dispersion media. Though the technique allows easy manufacture of ultrafine conductive silver patterns with a sufficiently high resolution, the technique relies on a peculiar characteristic of silver nanocolloids which exhibit a high dispersion stability and self-sintering characteristics after drying at room temperature. Despite the importance of these features for the printing technique, the origin of the unique dispersion stability is still unclear.
Here we report the dispersion characteristics of silver nanocolloids investigated by confocal dynamic light scattering (CDLS) technique. CDLS enables us to detect the size distribution of nanoparticles in the dispersion media. To investigate the effect of solvents on the dispersion stability, we changed the solvent composition and measured the stability of colloids by using CDLS.
| 氏名： 部谷
指導教員名： 中村 泰信 教授
発表題目（英語）： 2D integrated system design of superconducting qubits using 3D coaxial resonators
要旨（英語）： Implementation of efficient quantum error correction codes and realization of quantum computers using superconducting circuits require scalable two-dimensional integration of qubits. An obvious challenges is the wiring to access the qubits in the bulk part of the integrated circuits, not only the ones on the edges. We design and make a prototype to integrate qubits in 3D cavities and connect input/output ports vertically.
| 氏名： 廣木
指導教員名： 永長 直人 教授
発表題目（英語）： Spin current using non-centrosymmetric superconductors
要旨（英語）： In the past few years, spintronics has been active area of research. Spintronics is a device using spin current instead of electric current, and researches is conducted to generate spin current more efficiently. As part of those, some researchers have done research to generate spin current using superconductors. In previous works, there are researches to generate spin current on the edge, connection and interface of superconductors, but there are few works in the bulk superconductors. So, we do research spin current in bulk superconductors using spin triplet state with them. However pure triplet superconductors are very rare; therefore, we have focused singlet-triplet mixing non-centrosymmetric superconductors and studying spin current in them theoretically.
In this presentation, I will talk about the basis of general singlet superconductors in the first.
Next, I will talk about the basic theory of triplet and singlet-triplet mixing state in superconductors. In the last, I am going to talk about some previous works about spin current using non-centrosymmetric superconductors and what I am trying to do.
| 氏名： 堀
指導教員名： 酒 井 啓司 教授
発表題目（英語）： Gas viscosity measurement with magnetic-levitation EMS viscometer
要旨（英語）： Low-viscosity fluid is one of the important field in engineering and medical application, but there is only few method by which its viscosity can be measured with high precision.We recently developed the Magnetic-Levitation EMS (Electro-Magnetically Spinning) viscometer. In the method, mechanical friction is completely avoided because of the diamagnetic effect of the graphite probe. We measured the viscosity of mixed gases and low density gases with the method.The measured viscosity values we obtained from various kinds of gasses are well corresponded with literature values.In this presentation, we introduce the measurement principle of the magnetic-levitation EMS viscometer in detail, show the results of the gas viscosity measurement and its further application.
| 氏名： 深田
指導教員名： 石坂 香子 准教授
発表題目（英語）： Investigation of the electronic structure of a multi-layered Dirac electron system EuMnBi2 with an antiferromagnetic order
要旨（英語）： Dirac electron systems has been studied recently in solid-state physics due to their interesting physical properties, and the linear band dispersions were directly observed in some materials by ARPES(angle-resolved photoemission spectroscopy) measurement. Also, magnetic conductors exhibit various novel transport phenomena such as giant magneto resistive effect and anomalous Hall effect.
From these points, it is expected that further interesting physical properties and electronic structure will appear in a Dirac electron system with a magnetic order. In this context, we focused on the multi-layered Dirac electron system EuMnBi2, which has the Bi square lattice. In this system, Eu2+ ion having S = 7/2 is adjacent to the Bi square lattice that forms the pseudo two-dimensional Dirac electron system, and it is considered that the magnetic order of Eu can have some influences on Dirac electrons. Previous studies reported that the magnetic moment of Eu shows the antiferromagnetic transition at TN = 22 K.
To reveal the effects of antiferromagnetic order on the band structure of Dirac electron in this system, we performed ARPES measurements on EuMnBi2. In this talk, I will introduce the electronic structure of EuMnBi2 observed by ARPES experiments.
指導教員名： 十倉 好紀 教授
発表題目（英語）： Growth and magnetotransport properties of strongly correlated Dirac semimetal CaIrO3 thin film
要旨（英語）： In Dirac semimetal, which is one of the topological semimetals, several kinds of novel phenomena such as ultra-high mobility electron and giant magnetoresistance have been reported. So far, most studies focus on Dirac semimetals which can be well described within a framework of single-particle picture. However, recent theories predict that Dirac semimatal state with strong electron correlation is possibly realized in perovskite AIrO3 (A = Ca, Sr), thus it can be an ideal playground for studying the electron correlation effect or the coupling of several degrees of freedom including the topology of band structure in Dirac semimetal.
In this study, we prepared single crystalline thin film of CaIrO3 by the pulsed laser deposition (PLD) technique and measured magnetotransport properties. The unconventional B-linear-type magnetoresistance is observed at low temperatures, which may be an indication of the correlated Dirac electron of CaIrO3.