Leo Esaki

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Leo Esaki
江崎 玲於奈
Esaki with his invention of the tunnel diode at Sony, 1959
Born (1925-03-12) March 12, 1925 (age 100)[1]
Osaka, Empire of Japan
EducationThird Higher School
Alma materTokyo Imperial University (BS, PhD)
Known for
TitleIBM Fellow (1967–92)
Awards
See list
Scientific career
FieldsSolid-state physics
Institutions

Leo Esaki (/ɪˈsɑːki/ ih-SAH-kee;[2] Japanese: 江崎 玲於奈, romanized: Esaki Reona; born March 12, 1925) is a Japanese solid-state physicist who shared the 1973 Nobel Prize in Physics with Ivar Giaever and Brian Josephson for his work on tunneling in semiconductors, which led to his invention of the tunnel diode that exploits this phenomenon. His research was done when he was with Sony. He has also contributed in being a pioneer of the semiconductor superlattices.

Education and career

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Leo Esaki was born on March 12, 1925, in Osaka, Japan, and grew up in Kyoto, where he attended the Third Higher School. He then went on to study physics at Tokyo Imperial University (now the University of Tokyo).[3]

After graduating from UTokyo in 1947, Esaki joined the Kobe Kogyo company. In 1956, he became chief physicist at Tokyo Tsushin Kogyo (now Sony).[4]

In 1960, Esaki moved to the United States and joined the IBM Thomas J. Watson Research Center, where he was appointed an IBM Fellow in 1967.[5]

Research

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Tunnel diode

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Main article: Tunnel diode
1N3716 Esaki diode (with 0.1" jumper for scale)
Leo Esaki works at Sony on June 27, 1959 in Tokyo, Japan

In 1957, Esaki recognized that when the p-n junction width of germanium is thinned, the current-voltage characteristic is dominated by the influence of the tunnel effect and, as a result, he discovered that as the voltage is increased, the current decreases inversely, indicating negative resistance.[6] This discovery was the first demonstration of solid tunneling effects in physics, and it was the birth of a new electronic device called the tunnel diode (or Esaki diode), the first quantum electronic device in history. He received a Ph.D. from UTokyo due to this breakthrough invention in 1959.[1]

In 1973, Esaki was awarded the Nobel Prize in Physics for this work.[7] He became the first Nobel laureate to receive the prize from King Carl XVI Gustaf of Sweden.

Semiconductor superlattice

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In 1969, Esaki predicted that semiconductor superlattices will be formed to induce a differential negative-resistance effect via an artificially one-dimensional periodic structural changes in semiconductor crystals. His unique "molecular beam epitaxy" thin-film crystal growth method can be regulated quite precisely in ultrahigh vacuum. His first paper on the semiconductor superlattice was published in 1970.[8] A 1987 comment by Esaki regarding the original paper notes:

"The original version of the paper was rejected for publication by Physical Review on the referee's unimaginative assertion that it was 'too speculative' and involved 'no new physics.' However, this proposal was quickly accepted by the Army Research Office..."[9]

In 1972, Esaki realized his concept of superlattices in III-V group semiconductors, later the concept influenced many fields like metals and magnetic materials. He was elected a member of the National Academy of Engineering for contributions to the engineering of semiconductor devices in 1977. He was also awarded the IEEE Medal of Honor "for contributions to and leadership in tunneling, semiconductor superlattices, and quantum wells" in 1991,[10] and the Japan Prize "for the creation and realization of the concept of man-made superlattice crystals which lead to generation of new materials with useful applications" in 1998.[11]

Later life

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Esaki moved back to Japan in 1992. Subsequently, he served as president of the University of Tsukuba[1] and Shibaura Institute of Technology. Since 2006, he is the president of Yokohama College of Pharmacy. Esaki is also the recipient of The International Center in New York's Award of Excellence, the Order of Culture (1974) and the Grand Cordon of the Order of the Rising Sun (1998).

Since the death of Yoichiro Nambu in 2015, Esaki is the oldest Japanese Nobel laureate.

Esaki's "five don'ts" rules

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At the 1994 Lindau Nobel Laureate Meetings, Esaki suggested a list of "five don'ts" which anyone in realizing his creative potential should follow. Two months later, the chairman of the Nobel Committee for Physics Carl Nordling incorporated the rules in his own speech.[12]

  1. Don't allow yourself to be trapped by your past experiences.
  2. Don't allow yourself to become overly attached to any one authority in your field – the great professor, perhaps.
  3. Don't hold on to what you don't need.
  4. Don't avoid confrontation.
  5. Don't forget your spirit of childhood curiosity.

Recognition

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In recognition of three Nobel laureates' contributions, the bronze statues of Shin'ichirō Tomonaga, Leo Esaki, and Makoto Kobayashi were set up in the Central Park of Azuma 2 in Tsukuba City in 2015.[13]

Awards and honors

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List:[11]

Memberships in learned societies

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Family

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Esaki's daughter, Anna Esaki, is married to Craig S. Smith, former Shanghai bureau chief of The New York Times and China bureau chief of The Wall Street Journal.[14]

See also

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References

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  1. ^ a b c d Dr. Leo Esaki. japanprize.jp
  2. ^ "ESAKI Definition & Meaning". dictionary.com. Retrieved June 7, 2025.
  3. ^ "Leo Esaki - Research Profile". mediatheque.lindau-nobel.org. Retrieved August 16, 2025.
  4. ^ Leo Esaki | Biography, Nobel Prize, Tunnel Diode, & Facts. britannica.com. Retrieved August 16, 2025.
  5. ^ "Leo Esaki – Biographical". nobelprize.org. Retrieved August 16, 2025.
  6. ^ Esaki, L. (1958). "New Phenomenon in Narrow Germanium p-n Junctions". Physical Review. 109 (2): 603. Bibcode:1958PhRv..109..603E. doi:10.1103/PhysRev.109.603.
  7. ^ Esaki, Leo, "Long Journey into Tunneling," Nobel Lecture, December 12, 1973.
  8. ^ Esaki, L.; Tsu, R. (1970). "Superlattice and Negative Differential Conductivity in Semiconductors". IBM Journal of Research and Development. 14: 61–65. doi:10.1147/rd.141.0061.
  9. ^ "This Weeks's Citation Classic", Current Contents No 28, July 13, 1987.
  10. ^ "IEEE Medal of Honor Recipients" (PDF). Institute of Electrical and Electronics Engineers (IEEE). April 22, 2015. Archived from the original (PDF) on April 22, 2015. Retrieved August 9, 2019.
  11. ^ a b "The Japan Prize Foundation". www.japanprize.jp. Retrieved August 9, 2019.
  12. ^ Nordling, Carl (1995). "How to get the Nobel Prize in physics" (PDF). Physica Scripta. 59: 21–25. Bibcode:1995PhST...59...21N. doi:10.1088/0031-8949/1995/T59/001. S2CID 250817314.
  13. ^ "ノーベル賞:江崎、小林、朝永氏の銅像やレリーフ設置 完成記念式でお披露目 「子どもが夢を」−−つくば・中央公園 ／茨城 - 毎日新聞". Archived from the original on April 24, 2015. Retrieved August 9, 2019.
  14. ^ "Anna Esaki Wed To Craig S. Smith". The New York Times. January 14, 1990. ISSN 0362-4331. Retrieved August 19, 2021.

Further reading

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  • Large scale integrated circuits technology: state of the art and prospects, proceedings of the NATO Advanced Study Institute on "Large Scale Integrated Circuits Technology: State of the Art and Prospects," Erice, Italy, July 15–27, 1981 / edited by Leo Esaki and Giovanni Soncini (1982)
  • Highlights in condensed matter physics and future prospects / edited by Leo Esaki (1991)
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Media related to Leo Esaki at Wikimedia Commons