応用物理学輪講 I
6月21日
[注意事項]
発表の10日前までに　office[at]ap.t.u-tokyo.ac.jp　宛てに「氏名」「指導教員」「発表題目（英語）」「要旨（英語）」「発表言語（英語または日本語）」を送付して下さい。
発表日
2024年6月21日（金）16：50～18：50

Aグループ

座長
和田島　周星
指導
教員名
求　幸年　教授
発表者名 土田　真嗣
指導教員名 長谷川　達生　教授
発表題目（英語） Control of carrier injection at the ternary interface in inverted coplanar organic transistors
要旨（英語） Inverted coplanar organic thin-film transistors (OTFTs) are expected to be in practical use due to their structural advantages. However, inverted coplanar OTFTs do not show sufficiently high performance because they have large carrier injection barrier at the ternary interface where three different materials (organic semiconductor / electrode / insulator) are integrated. In this study, we controlled electrode work-function by adsorbing self-assembled monolayer (SAM) on the electrode and investigated the injection barrier at the ternary interface. Current decreased significantly as the work-function of electrode is lowered, even with nearly ideal transport interface. In addition, current was further reduced when using gate insulator with higher trap density. These results suggest that carrier accumulation at the ternary interface is important for efficient carrier injection. In this presentation, we will discuss the origin of the injection barrier based on the above experimental results.
発表言語 日本語
発表者名 首藤　龍馬
指導教員名 長谷川　達生　教授
発表題目（英語） Orientation and domain structures of plastic/ferroelectric [MDABCO][PF6] thin film
要旨（英語） Molecular ferroelectric crystals have attracted growing interest as potential alternatives to widely used ferroelectric perovskite oxides. Plastic/ferroelectric crystals are a new class of molecular ferroelectrics consisting of molecules with charge and polarity. It has been reported that plastic/ferroelectric crystals exhibit low-voltage and sharp switching due to multiaxial ferroelectricity originating from high crystal structures at high temperature. However, the fabrication of thin films by solution process and structures of domain walls (DWs) have not been revealed. In our research, we focus on a new plastic/ferroelectric crystal [MDABCO][PF6], which does not consist of rare metals and is expected for practical use. In this presentation, I will explain the fabrication methods and crystallographic orientation of thin films by water solution method, and formation mechanism of DWs which is revealed via domain visualization.
発表言語 日本語
発表者名 鈴木　拓海
指導教員名 古澤　明　教授　
発表題目（英語） All-optical quantum teleportation for ultrafast quantum computation
要旨（英語） An optical quantum computer is based on quantum teleportation.

As the frequency of light is several hundred THz, THz-clock optical quantum computers are feasible in principle. However, conventional quantum teleportation has been limited to the order of 100 MHz by the bandwidth of photoelectric conversion.

We therefore focused on "all-optical quantum teleportation", which utilizes optical parametric amplifiers to make measurements and feedforward without electrical signals.

I will present some achievements toward all-optical quantum teleportation.
発表言語 英語

Bグループ

座長
渡邊　瀬名
指導
教員名
渡辺　悠樹　准教授
発表者名 先崎　俊亮
指導教員名 川﨑　雅司　教授
発表題目（英語） Interfacial topological Hall effect at pyrochlore hetero interface of magnetic insulator Ln2Sn2O7 and non-magnetic metal Pb2Ru2O6.5
要旨（英語） Topological Hall effect is expected to emerge in magnetic metals with non-coplanar spin structure, in which the spin structure is topologically non-trivial in real space, and both experimental and theoretical research is being actively carried out.

The pyrochlore oxide Ln2Sn2O7 (Ln = Dy, Ho), known as classical spin ice, exhibits a peculiar magnetism with a non-coplanar spin structure and is expected to exhibit a topological Hall effect originating from the scalar spin chirality. However, Ln2Sn2O7 is an insulating material and cannot be evaluated for its electrical and magnetotransport properties on its own.

In my study, a hetero-interface sample was prepared by depositing a paramagnetic metal pyrochlore-type oxide Pb2Ru2O6.5 as an electrical conducting layer on Ho2Sn2O7. I succeed to fabricate hetero-structure and measured transport properties, so I will talk about it.
発表言語 日本語
発表者名 白石　蒼馬
指導教員名 吉岡　孝高　准教授
発表題目（英語） Efficient laser cooling of positronium
要旨（英語） Positronium is a bound state of electron and positron, both of which are leptons. Thus, it serves as a stringent testing ground for fundamental theories of physics, such as quantum electrodynamics through the measurement of its transition frequencies.
The low temperature is crucial for the accuracy of these measurements.
We succeeded in one-dimensional laser cooling approaching the recoil limit of positronium last year and are now aiming at three-dimensional laser cooling as the next step. Due to the limitation of the finite lifetime of positronium, it is essential to realize an efficient cooling method, which will be discussed in this talk.
発表言語 日本語
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