応用物理学輪講 I
11月8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11月8日（金）16：50～18：50

Aグループ

座長
佐藤　希宏
指導
教員名
香取　秀俊　教授
座長
清水　蓮也
指導
教員名
高橋　陽太郎　准教授
発表者名 佐藤　憩
指導教員名 長谷川　幸雄　教授
発表題目（英語） Introduction and Proposal for Nanoscale Thermometry Using Scanning Tunneling Potentiometry
要旨（英語） Thermal conduction is one of the most fundamental properties of materials. It is expected that there are differences between thermal transport at the macroscale and at the nanoscale due to size effects. Understanding thermal conduction at the nanoscale has become increasingly important from an application perspective, especially as device miniaturization has accelerated in recent years. Additionally, it is anticipated that quantum thermal conduction occurs at the nanoscale, characterized by electrons that do not dissipate energy due to electron-phonon or electron-electron interactions. However, conventional thermal measurement systems have a special resolution of several tens of nanometers, and the resolution for electron temperature is typically several tens to several hundreds of kelvins. These resolutions are insufficient to observe quantum thermal conduction or to expect practical applications in nanoscale devices. In this presentation, Scanning Tunneling Potentiometry (STP) is proposed as a promising measurement method for nanoscale thermometry. STP, based on Scanning Tunneling Microscopy (STM), offers atomic spatial resolution and microvolt-scale potential resolution. This presentation will introduce nanoscale thermometry methods using STP and related research.
発表言語 英語
発表者名 佐藤　陽紀
指導教員名 長谷川　達生　教授
発表題目（英語） Devlopment of organic FeFETs exhibiting highly-sharp swithching transistor operation
要旨（英語） Ferroelectric field-effect transistors (FeFETs) use ferroelectric materials as gate insulators, enabling low-energy, non-volatile devices. Several organic FeFETs based on organic semiconductors (OSCs) have been reported, but it is difficult to confirm their effectiveness, as many devices exhibit large subthreshold swing (SS) values, significant hysteresis, and high operating voltages. Recently, a novel approach has enabled the formation of extremely clean semiconductor interfaces by employing highly layered crystalline OSCs on highly lyophobic insulating layer surfaces, resulting in practical device performance with exceptionally sharp and stable switching at low voltages. In this study, I aim to develop high-performance organic FeFETs that leverage these sharp-switching characteristics. I will present the fabrication and characterization of thin films of the polymer ferroelectric PVDF-TrFE and report on FeFETs incorporating a hybrid gate insulating layer of lyophobic polymer and the ferroelectric PVDF-TrFE layer.
発表言語 日本語
発表者名 佐野　智紀
指導教員名 小芦　雅斗　教授
発表題目（英語） Quantum key distribution without monitoring eavesdropping
要旨（英語） Quantum key distribution (QKD) is attracting attention as a method of secret communication that is unaffected by improvements in computer performance or advances in algorithms. QKD is a method of creating a random number between two parties that is not leaked to a third party by using the properties of quantum theory. Usually, QKD uses the property of quantum theory that a disturbance occurs when there is eavesdropping to detect tapping from the errors and shorten the random number accordingly.

In this presentation, I introduce a protocol that makes eavesdropping impossible by using properties of quantum theory different from those of usual QKD protocols, and show that it has practical advantages and a new insight into the relationship between quantum theory and secret communication.
発表言語 日本語
発表者名 柴田　祐大
指導教員名 高橋　陽太郎　准教授
発表題目（英語） Exploring room temperature electromagnon shift current in multiferroics
要旨（英語） Direct conversion from terahertz photon to charge current is a key phenomenon for terahertz photonics. Quantum geometrical description of optical processes in crystalline solids predicts existence of field-unbiased dc photocurrent arising from terahertz-light generation of magnetic excitations in multiferroics, i.e. shift current induced by electromagnon, potentially leading to fast and energy-efficient terahertz devices. While this novel terahertz shift current has been indeed demonstrated in the archetypal multiferroics RMnO3 quite recently, its observation is still limited to the cryogenic temperature. In this talk, I will talk about the plan for realizing the high temperature terahertz shift current in Y-type hexaferrite. This material is known to show the magnetoelectric effect and electromagnon in terahertz region even at room temperature, providing the ideal platform. To this end, I have started the terahertz absorption spectroscopy under magnetic field.
発表言語 日本語

Bグループ

座長
首藤　龍馬
指導
教員名
長谷川　達生　教授
座長
白石　蒼馬
指導
教員名
吉岡　孝高　准教授
発表者名 白鳥　惇也
指導教員名 石坂　香子　教授
発表題目（英語） Study on photoinduced crystal structure dynamics by ultrafast electron diffraction
要旨（英語） In strong electron-phonon coupling, femtosecond pulse lasers induce cooperative crystal structure dynamics, such as photoinduced structural phase transitions and non-thermal phonon excitation. These dynamics have been investigated by ultrafast electron diffraction (UED), which provides time-resolved measurements of crystal structure in the photoexcited state. Recent developments in UED have enabled the quantitative refinement of crystal structures and the observation of phonon distributions in non-equilibrium conditions.

In this presentation, I will discuss two topics; (1) the quantitative analysis of the crystal structure dynamics of the photoinduced structural phase transition material VTe2, and (2) the observation of the excited two-dimensional chiral phonon in monolayer WSe2.
発表言語 日本語
発表者名 鈴木　滉平
指導教員名 芦原　聡　教授
発表題目（英語） Development of mode-locked Cr:ZnS laser for background-free spectroscopy
要旨（英語） Infrared spectroscopy is based on the vibrational absorption of light by molecules. The sensitivity of conventional methods of IR spectroscopy is limited by the dynamic range of the detector. In this presentation, I will introduce a new method called “Background-free Spectroscopy(BFS)”, which deletes the background light by destructive interference and enables detection of molecules beyond this limit. In addition, the development of a laser source for BFS adopting a Cr:ZnS crystal, a gain medium known for its wide emission spectrum in the IR region, would be explained in my talk. The oscillator is characterized by its self-starting mode-locked emission enabled by a single wall carbon nanotube saturable absorber.
発表言語 日本語
発表者名 鈴木　勇力
指導教員名 十倉　好紀　卓越教授
発表題目（英語） Emergent electromagnetic induction in magnetic Weyl semimetal PrAlGe
要旨（英語） Emergent electromagnetism is electromagnetism which is derived from spin degrees of freedom. In emergent electromagnetism, for example, topological magnetic structure, Skyrmion generates huge effective magnetic field or current-induced magnetization dynamics induces inductance which is inversely proportional to cross sectional area. Emergent electromagnetism makes these remarkeble phenomenon possible. Therefore, it is very important to research emergent electromagnetism to create innovative devices which replaces current devices based on classical electromagnetism. I’m going to talk about previous research on emergent electromagnetism and my research, generation of emergent electric field by new mechanism in magnetic Weyl semimetal PrAlGe.
発表言語 日本語
発表者名 砂田　桂花
指導教員名 中村　泰信　教授
発表題目（英語） Quantum state encoding in spatiotemporal modes of itinerant microwave photons
要旨（英語） uantum communication between distant superconducting qubits via itinerant microwave photons has been studied to realize distributed quantum computing. To enhance information capacity and fault tolerance in quantum networks, it is crucial to encode larger quantities of quantum information using auxiliary degrees of freedom of these photons. In this work, we experimentally explore the potential of utilizing spatiotemporal degrees of freedom.
This approach is promising as it allows for the generation of a large family of orthogonal modes temporally overlapping along a single propagation path through waveform engineering.

By employing the photon-shaping technique based on the temporal control of a microwave-driven parametric transition between a superconducting transmon qubit and a resonator coupled to it, we generate single itinerant photons in multiple orthogonal spatiotemporal modes propagating along a waveguide coupled to the resonator. We evaluate the efficiencies of the photon emission and the mode-selective absorption via the time-reversal process at the receiver. We discuss the effectiveness of utilizing spatiotemporal modes for quantum communication between remote superconducting qubits.
発表言語 日本語
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