Dr. Gento Yamahata

Biography

• 2020.10 - present: NTT Basic Research Laboratories
  Nanodevices Research Group in Advanced Applied Physical Science Laboratory
• 2010.4 - 2020.9: NTT Basic Research Laboratories
  Nanodevices Research Group in Physical Science Laboratory
  (2015.5 - 2015.7: Visiting researcher at National Physical Laboratory, UK)
• 2009.10 - 2010.3: Postdoctoral researcher at Tokyo Institute of Technology
  (2009.11 - 2010.1: Visiting researcher at Harvard University)
• 2009: Received Doctor of Engineering from Tokyo Institute of Technology
• 2005.4 - 2009.9: Department of Physical Electronics, Tokyo Institute of Technology
• 2001.4 - 2005.3: Department of Electrical and Electronic Engineering, Tokyo Institute of Technology

Research Interests

• Silicon high-speed single-electron transfer devices toward application to quantum current standards
  - OYO BUTURI Vol.87 No.2 p.121 (2018). (in Japanese)
  - NTT Technical Review (2015).
  - Our research was introduced in Vacuum and Surface Science (2018). (in Japanese)
• Electron transport through silicon quantum dots

Publications (first author)

    My Google Scholar Citations
    My ORCID

1. (New!) An ambipolar single-charge pump in silicon,
   G. Yamahata and A. Fujiwara,
   Applied Physics Letters 125, 163502 (2024). (arXiv:2408.01223)


2. Advances toward high-accuracy operation of tunable-barrier single-hole pumps in silicon,
   G. Yamahata and A. Fujiwara,
   Journal of Applied Physics 135, 014502 (2024). [Open access] (arXiv:2310.00875)


3. Coulomb collisions of hot and cold single electrons in series-coupled silicon single-electron pumps,
   G. Yamahata, N. Johnson, and A. Fujiwara,
   Physical Review Applied 20, 044043 (2023). (arXiv:2303.17242)
      - BRL annual report (2023).


4. Understanding the mechanism of tunable-barrier single-electron pumping: Mechanism crossover and optimal accuracy,
   G. Yamahata, N. Johnson, and A. Fujiwara,
   Physical Review B 103, 245306 (2021).
      - BRL annual report (2021).


5. Picosecond coherent electron motion in a silicon single-electron source,
   G. Yamahata, S. Ryu, N. Johnson, H.-S. Sim, A. Fujiwara, and M. Kataoka,
   Nature Nanotechnology 14, 1019-1023 (2019). (arXiv:1903.07802)
      - News and Views in Nature Nanotechnology 14, 1005-1006 (2019).
      - News release from NTT
      - News release from KAIST
      - BRL annual report (2019).


6. High-accuracy current generation in the nanoampere regime from a silicon single-trap electron pump,
   G. Yamahata, S. P. Giblin, M. Kataoka, T. Karasawa, and A. Fujiwara,
   Scientific Reports 7, 45137 (2017). [Open access]


7. Gigahertz single-electron pumping in silicon with an accuracy better than 9.2 parts in 10⁷,
   G. Yamahata, S. P. Giblin, M. Kataoka, T. Karasawa, and A. Fujiwara,
   Applied Physics Letters 109, 013101 (2016).
      - Editor's Picks in APL (Jul. 10, 2016)
      - News release from NTT
      - News release from National Physical Laboratory
      - Focus on the News in NTT GIJUTU Journal (in Japanese)
      - BRL activity report 27 (2016)


8. Gigahertz single-hole transfer in Si tunable-barrier pumps,
   G. Yamahata, T. Karasawa, and A. Fujiwara,
   Applied Physics Letters 106, 023112 (2015).
      - BRL activity report 26 (2015)


9. Gigahertz single-trap electron pumps in silicon,
   G. Yamahata, K. Nishiguchi, and A. Fujiwara,
   Nature Communications 5, 5038 (2014). [Open access]
      - News release from NTT
      - Picked up in natureasia.com (in Japanese)
      - Focus on the News in NTT GIJUTU Journal (in Japanese)
      - BRL activity report 25 (2014)


10. Accuracy evaluation and mechanism crossover of single-electron transfer in Si tunable-barrier turnstiles,
    G. Yamahata, K. Nishiguchi, and A. Fujiwara,
    Physical Review B 89, 165302 (2014).
       - BRL activity report 24 (2013)
    Erratum:
    Physical Review B 90, 039908(E) (2014).


11. Magnetic field dependence of Pauli spin blockade: a window into the sources of spin relaxation in silicon quantum dots,
    G. Yamahata, T. Kodera, H. O. H. Churchill, K. Uchida, C. M. Marcus, and S. Oda,
    Physical Review B 86, 115322 (2012). (arXiv:1111.6873)


12. Accuracy evaluation of single-electron shuttle transfer in Si nanowire metal-oxide-semiconductor field-effect transistors,
    G. Yamahata, K. Nishiguchi, and A. Fujiwara,
    Applied Physics Letters 98, 222104 (2011).
       - BRL activity report 22 (2011)


13. Control of Inter-Dot Electrostatic Coupling with a Side Gate in a Silicon Double Quantum Dot Operating at 4.5 K,
    G. Yamahata, T. Kodera, H. Mizuta, K. Uchida, and S. Oda,
    Applied Physics Express 2, 095002 (2009).
       - JSAP Young Scientist Award (2011).


14. Electron transport through silicon serial triple quantum dots,
    G. Yamahata, Y. Tsuchiya, H. Mizuta, K. Uchida, and S. Oda,
    Solid-State Electronics 53, 779-785 (2009).


15. Control of Electrostatic Coupling Observed for Silicon Double Quantum Dot Structures,
    G. Yamahata, Y. Tsuchiya, S. Oda, Z. A. K. Durrani, and H. Mizuta,
    Japanese Journal of Applied Physics 47, 4820-4826 (2008).

Publications (coauthor)

1. (New!) High frequency breakdown in quantum dots,
   N. Johnson, G. Yamahata, and A. Fujiwara,
   arXiv:2410.08932 (2024).


2. Sub-Femtoampere-Current Detection Using Single-Electron Sensor Operated Around 295 K,
   K. Nishiguchi and G. Yamahata
   IEEE Electron Device Letters 45, 1373-1376 (2024).


3. Universality and Multiplication of Gigahertz-Operated Silicon Pumps with Parts Per Million-Level Uncertainty,
   S. Nakamura, D. Matsumaru, G. Yamahata, T. Oe, D.-H Chae, Y. Okazaki, S. Takada, M. Maruyama, A. Fujiwara, and N.-H Kaneko,
   Nano Letters 24(1), 9-15 (2024).
      - News release from AIST (in Japanese)
      - News release from NTT (in Japanese)


4. Silicon quantum dot single-electron pumps for the closure of the quantum metrology triangle,
   A. Fujiwara, G. Yamahata, N. Johnson, S. Nakamura, and N.-H. Kaneko
   ECS Transactions 112, 119 (2023).


5. Cryogenic operation of electromechanical relay for reversal of quantized current generated by a single-electron pump,
   S. Nakamura, D. Matsumaru, G. Yamahata, T. Oe, Y. Okazaki, S. Takada, M. Maruyama, A. Fujiwara, and N.-H. Kaneko,
   IEEE Transactions on Instrumentation and Measurement 72, 1502809 (2023).


6. Precision measurement of an electron pump at 2 GHz; the frontier of small DC current metrology,
   S. P. Giblin, G. Yamahata, A. Fujiwara, and M. Kataoka,
   Metrologia 60, 055001 (2023). (arXiv:2301.04499)


7. Realisation of a quantum current standard at liquid helium temperature with sub-ppm reproducibility,
   S. P. Giblin, E. Mykkänen, A. Kemppinen, P. Immonen, A. Manninen, M. Jenei, M. Möttönen, G. Yamahata, A. Fujiwara, and M. Kataoka,
   Metrologia 57, 025013 (2020). (arXiv:1912.02042)


8. Measurement of the curvature and height of the potential barrier for a dynamic quantum dot,
   N. Johnson, G. Yamahata, and A. Fujiwara,
   Applied Physics Letters 115, 162103 (2019). (arXiv:1907.08445)


9. Evidence for universality of tunable-barrier electron pumps,
   S. P. Giblin, A. Fujiwara, G. Yamahata, M. -H. Bae, N. Kim, A. Rossi, M. Möttönen, and M. Kataoka,
   Metrologia 56, 044004 (2019). (arXiv:1901.05218) [Review paper]


10. Thermal-noise suppression in nano-scale Si field-effect transistors by feedback control based on single-electron detection,
    K. Chida, K. Nishiguchi, G. Yamahata, H. Tanaka and A. Fujiwara,
    Applied Physics Letters 107, 073110 (2015).


11. Simulation study of charge modulation in coupled quantum dots in silicon,
    T. Kambara, T. Kodera, T. Takahashi, G. Yamahata, K. Uchida, and S. Oda,
    Japanese Journal of Applied Physics 50, 04DJ05 (2011).


12. Vertical-coupled SiGe double quantum dots,
    C. B. Li, G. Yamahata, J. S. Xia, H. Mizuta, S. Oda, and Y. Shiraki,
    Electronics Letters 46, 940 (2010).


13. Position-controllable Ge nanowires growth on patterned Au catalyst substrate,
    C. B. Li, K. Usami, G. Yamahata, Y. Tsuchiya, H. Mizuta, and S. Oda,
    Applied Physics Express 2, 015004 (2009).


14. High-density assembly of nanocrystalline silicon quantum dots,
    A. Tanaka, G. Yamahata, Y. Tsuchiya, K. Usami, H. Mizuta, and S. Oda,
    Current Applied Physics 6, 344 (2006).

International conferences (since 2011)

1. Improved Accuracy of Single-Hole Pumping via Silicon Quantum Dot by Dynamic Gate Compensation,
   G. Yamahata and A. Fujiwara:
   36th International Conference on the Physics of Semiconductors 2024 (ICPS 2024)


2. Coulomb collisions in coupled Si single-electron pumps,
   G. Yamahata, N. Johnson, and A. Fujiwara:
   The 25th International Conference on Electronic Properties of Two-Dimensional Systems (EP2DS-25 2023)


3. Optimal accuracy of single-electron pumping using a dynamic quantum dot,
   G. Yamahata, N. Johnson, and A. Fujiwara:
   International Symposium on Novel maTerials and quantum Technologies (ISNTT 2021)


4. Effective Time-resolved Detection of Picosecond Coherent Dynamics in a Si Dynamic Quantum Dot,
   G. Yamahata, S. Ryu, N. Johnson, H.-S. Sim, A. Fujiwara, and M. Kataoka:
   International School and Symposium on Nanoscale Transport and phoTonics (ISNTT 2019)


5. Coherent oscillations of charge states in a Si single-electron pump at 4.2 K,
   G. Yamahata, S. Ryu, H.-S. Sim, N. Johnson, M. Kataoka, and A. Fujiwara:
   2018 International Conference on Solid State Device and Materials (SSDM 2018)


6. Mechanism of single-electron pumping via a single-trap level in silicon,
   G. Yamahata, S. P. Giblin, M. Kataoka, T. Karasawa, and A. Fujiwara:
   International School and Symposium on Nanoscale Transport and phoTonics (ISNTT 2017)


7. High-accuracy measurement of single-trap electron pumps in Si,
   G. Yamahata, S. P. Giblin, M. Kataoka, T. Karasawa, and A. Fujiwara:
   International Symposium on Advanced Nanodevices and Nanotechnology (ISANN 2015)


8. High-accuracy 2-GHz single-electron pumping in silicon,
   G. Yamahata, S. P. Giblin, M. Kataoka, T. Karasawa, and A. Fujiwara:
   International Symposium on Nanoscale Transport and Technology (ISNTT 2015)


9. Ultrafast single-charge transfer in silicon up to 8 GHz,
   G. Yamahata, K. Nishiguchi, S. P. Giblin, M. Kataoka, and A. Fujiwara:
   Silicon Quantum Electronics Workshop 2015


10. Gigahertz single-electron transfer via a single-trap level in silicon,
    G. Yamahata, K. Nishiguchi, M. Kataoka, and A. Fujiwara:
    The 21th international conference on Electronic Properties of Two-Dimensional Systems (EP2DS-21 2015)


11. Mechanism crossover of single-electron transfer in Si tunable-barrier turnstiles,
    G. Yamahata, K. Nishiguchi, and A. Fujiwara:
    International Symposium on Nanoscale Transport and Technology (ISNTT 2013)


12. Crossover of transfer mechanism in Si single-electron turnstiles,
    G. Yamahata, K. Nishiguchi, and A. Fujiwara:
    2013 International Workshop On Silicon Quantum Electronics


13. Accuracy of Single-electron Shuttle Transfer in Si Nanowire MOSFETs,
    G. Yamahata, K. Nishiguchi, and A. Fujiwara:
    The 19th international conference on Electronic Properties of Two-Dimensional Systems (EP2DS-19 2011)


14. Shuttling Transfer of Single Electrons in Si Nanowire MOSFETs,
    G. Yamahata, K. Nishiguchi, and A. Fujiwara:
    International Symposium on Nanoscale Transport and Technology (ISNTT 2011)

Awards

• The Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology.
  The Young Scientists' Award (2021).
  "High-accuracy single-electron control using silicon quantum dots."
     - List of award recipients.
• NTT Science and Core Technology Laboratory Group Director Award (2020).
  "Demonstration of ultimate energy saving and high-speed information processing by precise control of elementary charge dynamics"
• NTT Basic Research Laboratories Director Award for the paper (2020).
  Picosecond coherent electron motion in a silicon single-electron source,
  G. Yamahata, S. Ryu, N. Johnson, H.-S. Sim, A. Fujiwara, and M. Kataoka,
  Nature Nanotechnology 14, 1019-1023 (2019).
• NTT Basic Research Laboratories Director Award for the achievement (2019).
  "Realization of high-accuracy GHz operation of a single-electron pump toward application to current standards"
• NTT Science and Core Technology Laboratory Group Director Award (2014).
  "Research on high-accuracy and high-sensitivity electronics using single-electron manipulation and detection"
• JSAP Young Scientist Award (2011).
  Control of Inter-Dot Electrostatic Coupling with a Side Gate in a Silicon Double Quantum Dot Operating at 4.5 K,
  G. Yamahata, T. Kodera, H. Mizuta, K. Uchida, and S. Oda,
  Applied Physics Express 2, 095002 (2009).
• Tejima Research Award (2011).
• JSAP Young Scientist Oral Presentation Award (2008).
• The Poster Award for Nanotech in Japan, The 4th International Nanotechnology Conference on Communication and Cooperation (INC4 2008).

Other activities

• Selection committee of 46th JSAP Outstanding Paper Award (2024)
• Program committee of 2025 Silicon Nanoelectronics Workshop (SNW2025).
• Steering committee of 2025 International Conference on Solid State Devices and Materials (SSDM2025).
• Program committee of 2024 Silicon Nanoelectronics Workshop (SNW2024).
• Steering committee of 2024 International Conference on Solid State Devices and Materials (SSDM2024).
• Selection committee of 45th JSAP Outstanding Paper Award (2023)
• 2021.4 - 2023.3: Editorial committee of OYO BUTURI (JSAP membership journal).
• Steering committee of International Symposium on Nanoscale Transport and Technology (ISNTT 2015).

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