Dr. Gento Yamahata

Biography

• 2010.04 - Present: Nanodevices Research Group, Basic Research Laboratories, NTT, Inc.
  (2015.05 - 2015.07: Visiting Researcher, National Physical Laboratory, UK)
• 2009.10 - 2010.03: Postdoctoral Researcher, Tokyo Institute of Technology
  (2009.11 - 2010.01: Visiting Researcher, Harvard University)
• 2009: Doctor of Engineering, Tokyo Institute of Technology
• 2005.04 - 2009.09: Department of Physical Electronics, Tokyo Institute of Technology
• 2001.04 - 2005.03: Department of Electrical and Electronic Engineering, Tokyo Institute of Technology

Research Interests

• Silicon high-accuracy single-electron pumps for quantum applications
  - OYO BUTURI Vol.87 No.2 p.121 (2018). (in Japanese)
• Device physics for ultra-low-power and novel-function silicon electronics
  - Electron transport in silicon nanotransistors for cryogenic CMOS
  - Device functionality from the perspectives of information thermodynamics and nonequilibrium thermodynamics

Publications

    My Google Scholar Citations
    My ORCID

1. (New!) Thermodynamic Constraints in DRAM cells: Experimental Verification of Energy Efficiency Limits in Information Erasure,
   T. Shimizu, K. Chida, G. Yamahata, and K. Nishiguchi,
   Physical Review Letters 136, 117103 (2026). (arXiv:2505.23087)


2. (New!) High frequency breakdown in dynamic tunable-barrier quantum dots,
   N. Johnson, G. Yamahata, and A. Fujiwara,
   Physical Review Applied 24, 064045 (2025). (arXiv:2410.08932)


3. (New!) Scalable Parallel Single-Electron Pumps in Silicon with Split-Source Control in the Nanoampere Regime,
   G. Yamahata, T. Shimizu, K. Nishiguchi, and A. Fujiwara,
   Nano Letters 25(25), 10202-10208 (2025). (arXiv:2504.17273)


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


5. 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)


6. 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).


7. 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)


8. 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)
   


9. 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).


10. 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).


11. 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)


12. 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).
    


13. 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)


14. 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
    


15. 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)


16. 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]


17. 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]


18. 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
    


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


20. 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).


21. 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)
    


22. 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).
    Erratum:
    Physical Review B 90, 039908(E) (2014).


23. 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)


24. 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).


25. 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).
    


26. 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).


27. 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).
    


28. 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).


29. 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).


30. 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).


31. 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. Parallel Silicon Single-Electron Pumps for Generating Nanoampere Current,
   G. Yamahata, T. Shimizu, K. Nishiguchi, and A. Fujiwara:
   2025 Silicon Nanoelectronics Workshop (SNW2025).


2. 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)


3. 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)


4. 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)


5. 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)


6. 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)


7. 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)


8. 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)


9. 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)


10. 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


11. 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)


12. 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)


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


14. 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)


15. 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."
  
• 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"
  
• 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).
  
• 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

• Part-time Lecturer, Yokohama National University, 2026.4-
• Organizer for 251st ECS meeting, 2026.
• Program Committee Member, 2026 Silicon Nanoelectronics Workshop (SNW2026).
• Program Committee Member, JSAP Spring and Autumn Meetings (9.3 Nanoelectronics) 2025.4-
• Secretary of the Si Nanotechnology Research Committee, Silicon Technology Division, The Japan Society of Applied Physics (JSAP) 2025.4 -
• Program Committee Member, 2025 Silicon Nanoelectronics Workshop (SNW2025).
• Steering Committee Member, 2025 International Conference on Solid State Devices and Materials (SSDM2025).
• Member, Selection Committee for the 46th JSAP Outstanding Paper Award (2024).
• Program Committee Member, 2024 Silicon Nanoelectronics Workshop (SNW2024).
• Steering Committee Member, 2024 International Conference on Solid State Devices and Materials (SSDM2024).
• Member, Selection Committee for the 45th JSAP Outstanding Paper Award (2023).
• Editorial Committee Member, OYO BUTURI (JSAP membership journal), 2021.4 - 2023.3
• Steering Committee Member, International Symposium on Nanoscale Transport and Technology (ISNTT 2015).

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