Scientists investigate new ways of helping computers to keep their cool
In a scene from the sitcom The Big Bang Theory, the arrogant and awkward physics prodigy Sheldon Cooper asks a class of doctoral candidates at the California Institute of Technology if they are familiar with the concept of topological insulators.
All the students raise their hands, but when Cooper sarcastically comments “Oh, don’t kid yourselves!” every one of them lowers their hand in shame.
Whatever your feelings about the show, it got one thing right: topological matter is a notoriously difficult, albeit important, subject. So much so that four Nobel Prizes in physics, from 1985 to 2016, were awarded to experts who paved the way for its discovery.
However, most people are not aware that China is a major player in this cutting-edge field of condensed matter physics — the study of substances under different states.
One of the biggest names in the field is Xue Qikun, vice-president of Tsinghua University in Beijing, who led the team that discovered the quantum anomalous Hall effect in a magnetic topological insulator.
The effect can create “highways for electrons” in topological materials without the use of a strong magnetic field, which significantly reduces the energy needed to power electronic circuits. If used in everyday gadgets, the effect can greatly reduce heat dissipation, allowing engineers to design more compact and powerful computers, according to Xue.
In his Nobel lecture in Stockholm in 2016, Duncan Haldane, winner of that year’s prize in physics, said that while he laid the theoretical groundwork for the effect in the 1980s, Xue’s team took the next step and made the experimental observations.
The discovery, published in the journal Science in early 2013, sent a shock wave through the global physics community because it filled a theoretical gap that had puzzled scientists for more than 130 years. The journal’s reviewers called Xue’s discovery a “milestone” and “one of the most awaited phenomena in topological physics”.
In April 2013, Yang Chen-Ning, who won the Nobel Prize in physics in 1957, called Xue’s work “the first Nobel-prizeworthy physics paper from a Chinese lab”.
Top physics labs around the world, from Japan to the United States, have repeated and confirmed Xue’s findings in recent years.
President Xi Jinping has mentioned Xue’s work many times in speeches as an example of Chinese scientists breaking new ground in fundamental research. In January, Xue received first prize in the State Natural Science Award, China’s highest accolade for breakthroughs in basic research.
Born into a farming family in Shandong province in December 1963, Xue went from a rural student who failed his graduate school entry exam twice to a member of the Chinese Academy of Sciences and one of the country’s most accomplished physicists.
“Creating new scientific theory and discovering new phenomena and effects are the crown jewels of fundamental research,” Xue said. “The discovery of the quantum anomalous Hall effect represents a major contribution by Chinese