Kyushu University Academic Staff Educational and Research Activities Database
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Harada Yuichi Last modified date:2023.11.27

Graduate School
Other Organization

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 Reseacher Profiling Tool Kyushu University Pure
KOINE Project division
NanoFactory research platform
Cold Tech research platfomr .
Academic Degree
Ph. D.
Country of degree conferring institution (Overseas)
Field of Specialization
Condensed Matter Physics I, Superconducting device, Nanotechnology, and surface engineering
ORCID(Open Researcher and Contributor ID)
Total Priod of education and research career in the foreign country
Outline Activities
Considering the collaborative relationship between university and industry made me set up the KOINE concept. KOINE is the abbreviation of Kyudai global Open Innovation Network Engine, but it is an English word that originated from ancient Greek. Koine represents a common language. KOINE concept provides the opportunities to meet and discuss freely people with different backgrounds and we expect such discussion can create multidisciplinary research as well as new and innovative industrial applications. KOINE concept promotes various research platforms and we study what is the essence of innovative creation and how innovative idea comes out.
Research Interests
  • fabrication on superconducting qubits
    keyword : superconductivity, qubit, nanotechnology, ALD
  • Nanofabrication of carbon family
    keyword : carbon, nanotechnology
  • Freezing and thawing mechanisms on CAS
    keyword : CAS freezing thawing
  • Industrial-academia research collaborations based on KOINE model or Kyudai global Open Innovation Network Engine that is an original open innovation system.
    keyword : Open Innovation
  • Study on the management of the collaborative research projects among industry, academia, and government
    Innovative education
    keyword : management of the collaborative research
Current and Past Project
  • Developments on sustainable cooling
Academic Activities
1. Sameh Okashaa, Yoshiaki Sekine, Satoshi Sasaki, Yuichi Haradaa, Atomic layer deposition of aluminum (111) thin film by dimethylethylaminealane precursor, Thin Solid Films,, 732, 138784, 2021.06, We report the growth of aluminum (111) thin film by atomic layer deposition (ALD) technique with dimethy- lethylaminealane (DMEAA) as a precursor. It is found that the metallic underlayer is essential to grow uniform aluminum films by DMEAA precursor. As a titanium thin film is used as the underlayer, grown aluminum thin film shows (111) orientation irrespective of substrates. The lattice constant and superconducting transition temperature of the aluminum thin films are the same as the bulk one. These findings suggest that ALD technique provides high quality of the aluminum thin films and have potential for the applications of superconducting devices. We discuss ALD technique with DMEAA precursor is the promising method for fabricating vertical small Josephson tunnel junctions, which can be used as the superconducting quantum bits..
2. Hiroshi Irie, Clements Todt, Norio Kumada, Harada, Yuichi, Hiroki Sugiyama, Tatsushi Akazaki, Koji Muraki, Andreev reflection and bound state formation in a ballistic two-dimensional electron gas probed by a quantum point contact, Physical Review B, 10.1103/PhysRevB.94.155305, 94, 155305-6, 2016.10, We study coherent transport and bound state formation of Bogoliubov quasiparticles in a high-mobility In0.75Ga0.25As two-dimensional electron gas (2DEG) coupled to a superconducting Nb electrode by means of a quantum point contact (QPC) as a tunable single-mode probe. Below the superconducting critical temperature of Nb, the QPC shows a single-channel conductance greater than the conductance quantum 2e2/h at zero bias, which indicates the presence of Andreev-reflected quasiparticles, time-reversed states of the injected electron, returning back through the QPC. The marked sensitivity of the conductance enhancement to voltage bias and perpendicular magnetic field suggests a mechanism analogous to reflectionless tunneling—a hallmark of phase-coherent transport, with the boundary of the 2DEG cavity playing the role of scatterers. When the QPC transmission is reduced to the tunneling regime, the differential conductance vs bias voltage probes the single-particle density of states in the proximity area. Measured conductance spectra show a double peak within the superconducting gap of Nb, demonstrating the formation of Andreev bound states in the 2DEG. Both of these results, obtained in the open and closed geometries, underpin the coherent nature of quasiparticles, i.e., phase-coherent Andreev reflection at the InGaAs/Nb interface and coherent propagation in the ballistic 2DEG..
3. Harada, Yuichi, Iriel, Hiroshi, Sugiyama, Hiroki, Akazaki, Tatsushi, Josephson coupling through one-dimensional ballistic channel in semiconductor-superconductor hybrid quantum point contacts, PHYSICAL REVIEW B, 10.1103/PhysRevB.89.165415, 89, 16, 2014.04, We study a superconducting quantum point contact made of a narrow In0.75Ga0.25As channel with Nb proximity electrodes. The narrow channel is formed in a gate-fitted constriction of InGaAs/InAlAs/InP heterostructure hosting a two-dimensional electron gas.When the channel opening is varied with the gate, the Josephson critical current exhibits a discretized variation that arises from the quantization of the transverse momentum in the channel. The quantization of Josephson critical current persists down to the single-channel regime, providing an unambiguous demonstration of a semiconductor-superconductor hybrid Josephson junction involving only a single ballistic channel..
Membership in Academic Society
  • American Physical Society
  • Institute of Electrical and Electronics Engineers
  • The Institute of Electronics, Information and Communication Engineers
  • The Japan Society of Applied Physics
Educational Activities
Engagement of entrepreneurship education by practical research management theory based on open innovation 3.0, and research activities on nanotechnology and nanoscience.
Other Educational Activities
  • 2004.07, Innovation management at University of Oxford.
Professional and Outreach Activities
Mirai project between Japan and Sweden, Renkei project between Japan and UK.
Contribution to DX and entrepreneurship education in Nogata city based on the collaborative agreement.