John Bardeen (1908–1991) was an American physicist and electrical engineer who made groundbreaking contributions to the field of electronics. He is best known for co-inventing the transistor in 1947, alongside William Shockley and Walter Brattain, at Bell Labs, which revolutionized electronics and information technology. Bardeen also co-developed the theory of superconductivity, known as the BCS theory, with Leon Cooper and Robert Schrieffer in 1957. Remarkably, Bardeen is the only person to have won the Nobel Prize in Physics twice: first in 1956 for the transistor and again in 1972 for the BCS theory, cementing his legacy in science and technology.
Early Life and Education
John Bardeen was born on May 23, 1908, in Madison, Wisconsin, into an intellectually stimulating environment. His father, Charles Russell Bardeen, was the dean of the Medical School at the University of Wisconsin, and his mother, Althea Harmer Bardeen, was an accomplished scholar in her own right. Growing up in such an environment, Bardeen developed a keen interest in academics early on.
Bardeen’s early education was marked by his exceptional talent in mathematics and science. He attended the University of Wisconsin, where he initially pursued a degree in electrical engineering. His intellectual curiosity led him to take additional courses in mathematics and physics, laying the groundwork for his future scientific endeavors. Bardeen earned his bachelor’s degree in electrical engineering in 1928 and went on to complete his master’s degree in the same field in 1929.
Graduate Studies and Early Career
In 1930, Bardeen began his graduate studies at Princeton University under the guidance of physicist Eugene Wigner. His doctoral work focused on the quantum mechanical theory of the cohesive energy of metals, a topic that would become a recurring theme in his research career. Bardeen completed his Ph.D. in 1936, demonstrating his profound understanding of solid-state physics.
After receiving his doctorate, Bardeen joined the Department of Physics at the University of Minnesota. His research there was interrupted by World War II, during which he worked on defense-related projects, including the development of underwater mines at the Naval Ordnance Laboratory. This experience exposed him to practical engineering challenges and honed his problem-solving skills.
Bell Telephone Laboratories and the Transistor
In 1945, Bardeen joined Bell Telephone Laboratories, where he embarked on research that would change the course of modern electronics. At Bell Labs, Bardeen was part of a team tasked with understanding the limitations of vacuum tubes and exploring alternatives for signal amplification. Collaborating with physicist Walter Brattain and under the direction of William Shockley, Bardeen focused on the behavior of electrons at the surface of semiconductors.
The team’s breakthrough came in 1947 with the invention of the point-contact transistor. Bardeen and Brattain discovered that by placing two closely spaced gold contacts on a germanium crystal, they could control the flow of electrical current. This device, later refined into the more practical junction transistor by Shockley, revolutionized the field of electronics. The transistor was smaller, more reliable, and consumed less power than vacuum tubes, paving the way for the development of modern computers and electronic devices.
Recognition and Nobel Prize
The significance of the transistor could not be overstated. It marked the beginning of the semiconductor era and led to the rapid advancement of technology in the latter half of the 20th century. In 1956, Bardeen, Brattain, and Shockley were awarded the Nobel Prize in Physics for their discovery. Bardeen’s contribution was particularly noted for his theoretical insights into the behavior of semiconductors.
University of Illinois and Superconductivity
In 1951, Bardeen left Bell Labs to join the faculty at the University of Illinois at Urbana-Champaign. There, he continued his research in solid-state physics and took on the challenge of understanding superconductivity, a phenomenon where certain materials exhibit zero electrical resistance at very low temperatures. Despite being known since its discovery by Heike Kamerlingh Onnes in 1911, superconductivity lacked a comprehensive theoretical explanation.
Working with his graduate students, Leon Cooper and Robert Schrieffer, Bardeen developed the BCS theory, named after their initials. Published in 1957, the BCS theory explained superconductivity in terms of electron pairs, known as Cooper pairs, which move through a lattice structure without resistance. This groundbreaking work provided a microscopic explanation of superconductivity and laid the foundation for future research in the field.
Second Nobel Prize
Bardeen’s work on superconductivity was met with widespread acclaim, and in 1972, he, along with Cooper and Schrieffer, was awarded the Nobel Prize in Physics. Bardeen became the first person to win the Nobel Prize in Physics twice, a testament to his profound contributions to science and technology.
Personal Life and Legacy
Despite his monumental achievements, Bardeen was known for his modesty and dedication to teaching and mentoring. He married Jane Maxwell in 1938, and together they had three children. Bardeen was a devoted family man, and his humility and kindness were well-known among his colleagues and students.
John Bardeen passed away on January 30, 1991, leaving behind a legacy of scientific excellence and innovation. His contributions to the fields of solid-state physics and superconductivity have had a lasting impact, shaping the technological landscape of the modern world. The transistor and the BCS theory remain cornerstones of modern electronics and physics, underscoring Bardeen’s role as one of the greatest scientific minds of the 20th century.