Leroy Chang

Leroy Li-Gong Chang (; January 20, 1936 – August 10, 2008) was a Taiwanese–American solid-state physicist. Born in China, he studied in Taiwan and then the United States, obtaining his doctorate from Stanford University in 1963. As a research physicist, he studied semiconductors for nearly 30 years at the Thomas J. Watson Research Center in New York. This period included pioneering work on superlattice heterostructures with Nobel Prize-winning physicist Leo Esaki.

In 1993, Chang moved from New York to Hong Kong, switching from industrial research into academia in anticipation of the 1997 transfer of the British colony to China. He was among the first wave of recruits to the Hong Kong University of Science and Technology. Over the following 14 years, he helped build the university's reputation in his roles as Dean of Science, Professor of Physics, Vice President of Academic Affairs, and professor emeritus.

Honors bestowed on Chang included memberships of the National Academy of Sciences, the Chinese Academy of Sciences, and Academia Sinica—the national academy of Taiwan. Awards received included the International Prize for New Materials (1985), the David Sarnoff Award (1990), and the Stuart Ballantine Medal (1993). Chang's death in 2008 was marked with memorial services, and a symposium in his memory was held the following year.

Early life and education Leroy Li-Gong Chang's family was from Jiutai County, Jilin province, in Northeast China (Manchuria). After Manchuria was invaded by Japan in 1931, his family escaped to inland China and Chang was born on January 20, 1936, in Kaifeng, Henan province. His father, , was a well-known geologist and government official who was assassinated by the Communists in 1946, which prompted the family to move to Taiwan. His mother, Li Xiangheng, was one of the first group of women elected to the Legislative Yuan in 1948.

Chang studied electrical engineering at National Taiwan University, graduating with a B.S. in 1957. He emigrated to the United States in 1961 to continue his studies, receiving his Ph.D. in Electrical Engineering from Stanford University in 1963.

Career and research IBM Between 1963 and 1992, Chang worked at IBM's Thomas J. Watson Research Center in New York. He held the position of researcher for some twelve years (1963–1968; 1969–1975), with a sabbatical year as Associate Professor in the Department of Electrical Engineering at the Massachusetts Institute of Technology (1968–1969). On his return to IBM research, he spent nine years as manager of its Molecular Beam Epitaxy section (1975–1984). This was followed by seven years as manager of the Quantum Structure section (1985–1992). In the 1970s, he pioneered development of quantum well and superlattice structure (SLS) techniques. Eleven years later, in 1984, this pioneering research paper was featured as a Citation Classic by the ISI, an organization that tracks and measures impact factor and citation frequency and volume for journals and individual research papers. Commentary for this retrospective article was provided by Chang. The impact of the research carried out in the 1970s by Chang and his colleagues, including Nobel Prize-winning Leo Esaki and Raphael Tsu, was highlighted by IBM researchers Theis and Coufal in 2004:

Leo Esaki, Ray Tsu, and Leroy Chang began to envision and investigate designed quantum structures — which are based on interfaces between lattice-matched compound semiconductors — early in the 1970s. Ever since, the study of electronic systems of minute dimensions has ranked among the most exciting areas of condensed-matter physics.

HKUST After 29 years at IBM, Chang moved from industrial research into academia, being appointed the first Dean of Science at the Hong Kong University of Science and Technology (HKUST) in 1993. This was a new university, having been established in 1991. Chang's arrival was described in a 2011 account of the rise of this university: "Other recruits during the first decade included Leroy Chang, a world-renowned experimental physicist from International Business Machines (IBM)." He held the position of Dean of Science until 1998, when he became Vice President of Academic Affairs—stepping down from this role in 2000. From 1997 until his retirement in 2007, he was also University Professor of Physics. Quoted in an article in 1996, Chang stated:

I would never have come to Hong Kong if it was going to remain just a British colony. We came because of 1997. Leslie is an author and journalist who is married to Peter Hessler, author of several books about China.

Death and tributes Chang died on August 10, 2008, at the age of 72. The symposium program included "A Tribute to Academician Leroy Chang" and "Remembering Leroy: from SL/QW to RCAS". At the time of his death, tributes were paid to Chang by his HKUST colleagues, including the university's founding president Chia-Wei Woo:

Leroy was always exuberant and high-spirited, logical and sensible, forceful and clear, efficient and effective – and always full of wit and humor. As Dean of Science and Vice-President for Academic Affairs, he gave up his beloved and world-renowned scientific career to work totally selflessly towards providing a sound academic environment for his colleagues. HKUST's founding members could not have had a stronger comrade-in-arms in building this new university. I so very deeply mourn his passing. 1990 IEEE IEEE David Sarnoff Award "For pioneering contributions to the realization and development of quantum wells and superlattices." 1993 Franklin Institute Stuart Ballantine Medal "For applications of semiconductor P." 1988 National Academy of Engineering Member 1990 IEEE Fellow 1994 National Academy of Sciences Member 1994 Academia Sinica Academician Honorary degrees Year University Degree 1995 HKUST Doctor of Science