A Chinese professor previously accused of espionage has assisted in the discovery of what the Massachusetts Institute of Technology (MIT) has dubbed the “best semiconductor material ever found.” MIT professor Gang Chen was among the number of Chinese researchers in U.S. universities who were prosecuted over alleged ties to the Chinese government in recent years. Last year, he was arrested by federal agents but was eventually cleared by the Department of Justice of espionage charges due to a lack of evidence. Eight months later, he was among the team at MIT, the University of Houston and other research centers that...