座長： 高橋 健吾、西野 隆太郎
| 氏名： 村瀬
指導教員名： 鹿野田 一司 教授
発表題目（英語）： Electrical transport properties of θ-(ET)2I3 under uniaxial pressure
要旨（英語）： In the quasi two dimensional triangular lattice organic conductor θ-(ET)2X(X=TlCo(SCN)4, RbZn(SCN)4, CsZn(CSN)4, I3 and so on) system, conventionally, various electronic states including charge ordering, fermi liquid and superconducting have been described according to the dihedral angle formed by the ET molecules, but electronic glass states beyond this framework were discovered. In the electronic glass, the electric states are understood by the geometrical frustration of the triangular lattice which causes the degeneracy of the macroscopic number of eigen energies and is regard as the origin of electric glass state.
This study measured the electric resistivity of θ-(ET)2I3 while distorting it by uniaxial pressure in order to understand uniformly the electronic states of the θ-(ET)2X system including the electron glass state by the new axis of the geometrical frustration.
In this talk, the relationship between the geometrical frustration and electronic states will be discussed.
発 表言語： 日本語
| 氏名： 横澤
指導教員名： 樽茶 清悟 教授
発表題目（英語）： Towards interlayer exciton valley Hall effect in van der Waals heterostructures of transition metal dichalcogenides.
要旨（英語）： Valley degree of freedom has recently attracted much attention as a new information carrier. One of the most promising platforms for valley manipulation is layered honeycomb lattice materials, such as graphene and transition metal dichalcogenides (TMDCs). TMDC has moderate band gap enabling optical access while graphene has no or only a small gap. However, crystal quality of TMDC is lower than graphene so that valley relaxation time is shorter. In certain van der Waals heterostructures of TMDC, optically excited electrons and holes immediately separate to different layers and form interlayer excitons (IXs), which have longer valley life time. Furthermore, out-of-plain electric dipole of IX may allow us to drive it and generate exciton flow electrically. Additionally, by driving IX flow, valley Hall effect (VHE) and valley current are expected to be observed.
In this presentation, I will talk about my research towards VHE using IX in TMDC. Especially, I will focus on how to fabricate samples, and problems in the processes.
| 氏名： 山岡
指導教員名： 酒井 啓司 教授
発表題目（英語）： Measurement of dynamic surface and interfacial tension by shape analysis of flying droplets
要旨（英語）： We have developed the method for measurement of dynamic surface and interfacial tension in the very high-speed time domain of several hundreds of microseconds to a few milliseconds. In this method, temporal change of surface and interfacial tension ratio can be observed from the shape analysis of flying Dharma-shaped droplets, which are formed by collision of immiscible and incompletely-wetting liquid droplets. In the previous research, the measurement accuracy was not good, and furthermore the dynamic properties were not obtained. By improving the experimental system and the parameters to be used, the higher accuracy and the dynamic measurement were successfully achieved. In this presentation, I will show you the details of this experiment and measurement results of dynamic surface and interfacial tension ratio after the collision between surfactant aqueous solution and hexadecane.
| 氏名： 渡
指導教員名： 十 倉 好紀 教授
発表題目（英語）： Interfacial conductive channel and anomalous Hall effect in MnTe/InP
要旨（英語）： Recently, interface conductivity and interface magnetism is getting a lot of attention.
In this study, MnTe thin film is grown on insulating InP substrate with Molecular Beam Epitaxial(MBE) method. Manganese telluride have been known as a antiferromagnetic(AFM) semiconductor and InP substrate is non-magnetic semiconductor.
From the thickness dependence of transport properties, it was confirmed that a conductive layer is formed in the vicinity of the interface. In magnet transport measurement, anomalous Hall effect implying the existence of ferromagnetic order is also observed below 240 K.
This result suggests the existence of unknown magnetic order at the interface of MnTe/InP. I’ll discuss the possible origin of anomalous interface properties.