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Leo Esaki

From Alfawiki
Leo Esaki
Born (1925-03-12) March 12, 1925 (age 101)
Takaida-mura, Nakakawachi-gun, Osaka Prefecture, Japan (now part of Higashiōsaka City)
OccupationPhysicist
Known forDiscovery of the Esaki diode (tunnel diode), semiconductor superlattices, quantum tunneling phenomena
Notable workDevelopment of the tunnel diode, research on semiconductor superlattices

Leo Esaki ( ; ; born March 12, 1925) is a distinguished Japanese physicist specializing in solid-state physics. He was co-recipient of the 1973 Nobel Prize in Physics alongside Ivar Giaever and Brian Josephson for his groundbreaking investigations into quantum tunnelling phenomena within semiconductor materials. His research at Tokyo Tsushin Kogyo (present-day Sony) culminated in the creation of the tunnel diode, a pioneering device that leverages quantum tunneling effects. Additionally, Esaki was instrumental in developing semiconductor superlattice structures.[1]

Early life and education

Esaki was born in Takaida-mura, Nakakawachi-gun, Osaka Prefecture (currently part of Higashiōsaka City) and spent his formative years in Kyoto. His education included attendance at Doshisha Junior High School followed by the Third Higher School. He pursued physics at Tokyo Imperial University, where he studied nuclear theory under Hideki Yukawa and lived through the Bombing of Tokyo.[2]

He completed his Bachelor of Science degree in 1947 and later obtained his PhD from the University of Tokyo in 1959.

Esaki diode

Between 1947 and 1960, Esaki was employed at Kawanishi Corporation (now known as Denso Ten) and Tokyo Tsushin Kogyo (currently Sony). Motivated by the transistor invention by American scientists John Bardeen, Walter Brattain, and William Shockley, he transitioned from vacuum tube research to intensive studies on heavily doped germanium and silicon semiconductors at Sony. In 1958, he discovered that reducing the thickness of the PN junction in germanium results in a current-voltage behavior dominated by electron tunneling, producing negative resistance characteristics. This discovery led to the development of the Esaki diode (also called the tunnel diode), recognized as the first quantum electronic component. For this accomplishment, he was awarded a doctorate from the University of Tokyo in 1959.

Esaki's pioneering work on electron tunneling in solids during the late 1950s earned him the Nobel Prize in 1973. Notably, he was the first laureate to be presented with the prize by King Carl XVI Gustaf of Sweden.

Semiconductor superlattice

In 1960, Esaki relocated to the United States to join IBM's Thomas J. Watson Research Center, where he was named an IBM Fellow in 1967. He theorized about semiconductor superlattices, which are engineered one-dimensional periodic crystal structures exhibiting negative differential resistance. Utilizing his refined "molecular beam epitaxy" technique for thin-film deposition under ultrahigh vacuum conditions, he published a foundational paper on these superlattices in 1970.

Although initially rejected by Physical Review, his ideas eventually gained widespread recognition, influencing research across metals and magnetic materials as well. By 1972, Esaki successfully fabricated superlattices using III-V semiconductor compounds. His contributions to semiconductor devices led to his election to the National Academy of Engineering in 1977, and he received the prestigious IEEE Medal of Honor in 1991 for his innovative leadership involving tunneling phenomena, superlattices, and quantum wells. In 1998, Esaki was honored with the Japan Prize for his creation and realization of artificial superlattice crystals that paved the way for novel materials with practical applications.

Esaki's "Five Don'ts" Principles

During the 1994 Lindau Nobel Laureate Meetings, Esaki presented his "five don'ts" guidelines aimed at unlocking creative abilities, which were later reiterated by Nobel Committee chairman Carl Nordling:

  1. Avoid being limited by previous experiences.
  2. Refrain from excessive reliance on any established authority in your discipline.
  3. Let go of what is unnecessary.
  4. Embrace conflict rather than evade it.
  5. Maintain the inquisitiveness of your youth.

Later Life

In 1992, Esaki returned to Japan and took leadership roles as president of both the University of Tsukuba and the Shibaura Institute of Technology. Since 2006, he has been at the helm of Yokohama College of Pharmacy. Among his accolades are The International Center in New York's Award of Excellence, the Order of Culture awarded in 1974, and the Grand Cordon of the Order of the Rising Sun received in 1998. Following the passing of Yoichiro Nambu in 2015, Esaki became recognized as the oldest living Japanese Nobel laureate.

Acknowledgments

In 2015, bronze sculptures commemorating three Nobel Prize winners—Shin'ichirō Tomonaga, Leo Esaki, and Makoto Kobayashi—were placed in Tsukuba City's Central Park of Azuma 2.

Distinctions and Awards

Affiliations with Academic Institutions

  • 1960 – Fellow, American Physical Society
  • Member, Physical Society of Japan
  • 1975 – Member, Japan Academy
  • 1976 – Foreign Associate, National Academy of Sciences
  • 1977 – Foreign Associate, National Academy of Engineering
  • 1989 – Member, Max Planck Society
  • 1991 – Member, American Philosophical Society
  • 1994 – Foreign Member, Russian Academy of Sciences
  • 1995 – Honorary Foreign Member, Korean Academy of Science and Technology
  • 1996 – Member, Accademia dei Lincei

Family

Esaki's daughter Anna is married to Craig S. Smith, who formerly served as Shanghai bureau chief for The New York Times and as China bureau chief for The Wall Street Journal.

See also

Further reading

  • 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)

External links

  1. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named jp
  2. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Bio
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