Houston scientist Dr. Paul Chu upends the physics world with superconductivity breakthrough
Thousands of scientists crammed the hallways of the Hilton Hotel in New York, jockeying for a seat inside the ballroom. Televisions were set up for the unlucky who couldn’t squeeze inside for the event, which would later be dubbed the “Woodstock of Physics.”
It was March 1, 1987, and just a few weeks earlier a Houston scientist named Paul Chu had turned the world of physics upside down by announcing he had created a material - a calculated mix of yttrium, barium, copper and oxygen - that could conduct electricity with no resistance. And he had done it at the “high” temperature of 93 degrees Kelvin, breaking a barrier many in the science community weren’t sure could be crossed.
Chu’s discovery of a high-temperature superconductor promised to usher in a new age of electricity distribution and storage, transportation and computing.
And while a technological revolution never occurred, it did establish Chu as one of Houston’s most prominent scientists and made the city an epicenter of superconductivity research that continues today under the goal of pushing the temperature threshold higher, to room temperature or more.
“Based on our previous analyses, we can get to room temperature,” Chu said. “The question is when and how? I’m not sure but the possibility is getting close.”
Almost 30 years after Chu’s seminal paper on superconductivity was published, he remains bullish about the field, which continues to spin off new fields of research.
He teaches and continues to be a looming presence at the Texas Center for Superconductivity, which was established at the University of Houston not too long after Chu’s discovery.
Today it employs more than 200 people, many of whom were drawn to Houston because of Chu’s reputation as a pioneer in the field.
“One thing about Paul is he’s a scientist who is still hard at work at being a scientist,” said Allan Jacobson, the center’s executive director. “He’s not done.”
Nothing is impossible in Houston
Born in Taiwan, Chu, then known as Ching Wu, grew up interested in science, drawn to anything that was electric or magnetic.
As a young boy, he would sift through the junkyards of Ching Shui, his hometown, looking for parts to build a radio and a small motor.
He came to the United States for his master’s degree at Fordham University. After obtaining it in 1965, he earned his doctorate at the University of California, San Diego.
He arrived in Houston in 1979 to accept a job as a physics professor because he said, “that was the boom time of Houston, and nothing seemed to be impossible in Houston.”
What did seem impossible, however, was high-temperature superconductivity.
Superconductivity was discovered in 1911 by a Dutch scientist working with mercury he cooled with liquid helium.
Before 1987, the phenomenon only had been observed when material was chilled to near absolute zero, around 4 degrees Kelvin.
Pushing the temperature higher was the stuff of fantasy.
Nonetheless, it was pursued by an endless cadre of scientists.
In 1986, some IBM scientists in Germany announced they had created a ceramic compound that could be a superconductor at 35 degrees Kelvin. The discovery set off a race among scientists to reproduce the results and possibly come up with a better concoction.
Within a year, Chu unlocked the secrets of superconductivity on his own, creating a compound known as YBCO, which could function at an astonishing 93 degrees Kelvin.
Getting to that temperature meant the material could be cooled by cheap, abundant liquid nitrogen.
The physics world reacted with a collective gasp. Many predicted Chu’s superconductor would quickly lead to the creation of better power lines, trains, motors and all sorts of electronic devices.
Weeks after his paper was published, the Houston Chronicle trumpeted a Nobel Prize for Physics was likely for Chu and his discovery could earn billions for UH.
The courting of Chu
“It was not a surprise to me,” Chu said of the fallout of his discovery. “Because this whole thing was expected by people for decades since 1911 after its initial discovery. So all of a sudden we reached that stage. It was quite natural that everyone was excited about it.”
Chu didn’t win the Nobel - that honor went to the two German scientists - but he did pick up several other top science prizes and most of the publicity for superconductivity research. Consequently, there was a concerted effort among the nation’s top academic institutions to pluck him from UH.
Hottest on his heels was the University of California at Berkeley. But his mentor, C.N. Yang, the first Chinese American to win the Nobel Prize for Physics, told him he could have a larger effect in the world of science if he stayed in Houston.
“At the time, people in Houston, the state of Texas, they’re very nice to me,” he said.
Indeed they were.
Moving with speed unheard of in today’s political world, Texas legislators approved legislation that established the Texas Center for Superconductivity at UH, a place where Chu could continue pushing the temperature barrier for superconductors. He was appointed the center’s first director and a cadre of the world’s top physicists packed their bags and headed to Houston.
“A large number of our students have gone on to become leaders in the field as well as leaders in government and industry,” said Jacobson, who became the center’s director in 2005. “Paul was instrumental in bringing many of them here.”
Still reaching for room temperature
In the years following Chu’s discovery, he and other scientists made another discovery: creating superconductors at higher temperatures for commercial applications is a costly enterprise.
So now they are trying to do one of two things - improve the material by raising the temperature at which superconductivity occurs, or improve the material’s overall performance.
Chu’s team has pushed the temperature to 164 Kelvin and a German scientist published a paper in 2015 that indicates he’s hit 203 Kelvin. Room temperature is around 300 Kelvin.
“But if you look at history, we raised the temperature from 35 to 93 degrees almost overnight,” Chu said. “So why couldn’t we repeat this?
Today, at 75, he shows no signs of stopping.
Even if he never breaks another superconductivity record, Chu said he’s at peace with that.
“One can only do his or her best and let nature decide the outcome,” he said.