Karl Alexander Müller

Karl Alexander Müller was a Swiss physicist whose groundbreaking work revolutionized the field of condensed matter physics. He is best known for the 1986 discovery, with his colleague J. Georg Bednorz, of high-temperature superconductivity in a ceramic material, a breakthrough that shattered long-held theoretical limits. This seminal achievement earned them the Nobel Prize in Physics in 1987 and ignited a global surge of research into novel superconducting materials. Müller's career was primarily spent at the IBM Research – Zurich laboratory, where he pursued research in perovskite structures and oxide materials.

Early life and education

Karl Alexander Müller was born in Basel and spent his early childhood in Salzburg and Austria before his family returned to Switzerland. His interest in science was sparked by reading popular works and by a teacher at the Evangelical School Schiers, a Gymnasium in Graubünden. After completing his Matura, he briefly served in the Swiss Armed Forces before commencing his university studies. Müller enrolled at the ETH Zurich, where he studied under prominent physicists including Wolfgang Pauli and earned his Diploma in 1958. He completed his doctorate in 1958 under the supervision of G. Busch, with a thesis on the photoconductivity of graphite.

Career and research

Müller began his research career at the Battelle Memorial Institute in Geneva, focusing on semiconductors and ferroelectricity. In 1963, he joined the prestigious IBM Research – Zurich laboratory in Rüschlikon, where he would remain for the rest of his professional life. His early work at IBM included significant studies on strontium titanate and other perovskite oxides, investigating phenomena such as quantum paraelectricity and the metal–insulator transition. He also held a professorship at the University of Zurich from 1970 to 1994. Müller's deep expertise in the structural and electronic properties of transition metal oxides provided the essential foundation for his later historic discovery.

Discovery of high-temperature superconductivity

In the early 1980s, Müller, motivated by theoretical ideas from the BCS theory and the work of others on charge density waves, deliberately sought superconductivity in oxide systems. He partnered with a younger researcher at IBM, J. Georg Bednorz, to systematically investigate lanthanum barium copper oxide compounds. In 1986, they published their landmark paper in the journal Zeitschrift für Physik, reporting superconductivity at a then-record temperature of 35 Kelvin in a ceramic material. This discovery of a cuprate superconductor, which shattered the perceived "glass ceiling" of about 30 K, was rapidly confirmed by teams at the University of Tokyo and University of Houston. It led to an unprecedented international race that soon produced materials like YBCO that superconducted above the temperature of liquid nitrogen.

Awards and honors

The impact of Müller's discovery was immediately recognized with numerous prestigious awards. In 1987, he and Bednorz were jointly awarded the Nobel Prize in Physics, just a year after their publication, one of the fastest recognitions in the prize's history. That same year, they also received the Moscow International Prize. Earlier, in 1986, Müller had been honored with the Marcel Benoist Prize, often called the "Swiss Nobel Prize." His other accolades include the Fritz London Memorial Prize, the Dannie Heineman Prize, the Robert Wichard Pohl Prize, and the Japan Prize. He was a member of numerous academies, including the United States National Academy of Sciences and the Russian Academy of Sciences.

Personal life and legacy

Karl Alexander Müller was known for his modest and thoughtful demeanor. He was married and had two children. Beyond his scientific work, he had a keen interest in history and philosophy of science. His legacy is profound, having single-handedly redirected the course of solid-state physics and materials science. The discovery of high-temperature superconductivity opened a vast new field of research, leading to thousands of studies on cuprate superconductors, the pseudogap phase, and potential applications in technologies like maglev trains and MRI machines. He passed away in Zürich in 2023, remembered as a pivotal figure who demonstrated that revolutionary discoveries could still be made in well-explored areas of physics.

Category:Swiss physicists Category:Nobel laureates in Physics Category:1927 births Category:2023 deaths