Physics professor Xiaolong Liu furthers quantum physics research with development of new device

Author: Caroline Crawford

Xiaolong Liu

Xiaolong Liu, assistant professor in the Department of Physics and Astronomy, studies novel quantum states of matter including unconventional superconductivity. His lab works to image the wave functions of electrons in complex materials.

Previously it was not possible to image pairs of electrons, only single electrons. Liu studies superconductors, and their ground state—their lowest-energy state—is a two-electron system formed by pairs of electrons. Since previous technology could not image this directly, Liu developed a microscope that can do so at the atomic scale. His invention is a special kind of scanning tunneling microscope, which is a device capable of imaging surfaces at an atomic level by means of an extremely sharp superconducting tip.

“That kind of behavior has almost never been observed before,” Liu said. “But because we developed this scanned Josephoson tunneling microscope, we are now able to observe it down to the atomic scale for the first time.”

Liu’s technology helps scientists and engineers better understand quantum materials, which is necessary for further development of quantum computers and other emerging quantum technologies.

Liu’s research has already garnered a great deal of attention in the scientific community. For his postdoctoral work, Liu received the Blavatnik Regional Award in Physical Sciences and Engineering, a prestigious award recognizing promising young scientists.

Liu looks forward to continuing his research at the University of Notre Dame. He remarked that Notre Dame offers great opportunities for young scientists in quantum physics, and he appreciates the freedom he has in constructing and designing his lab.

“Notre Dame is a very good platform for me to continue my research,” Liu said.

He also enjoys working with undergraduate and graduate students who are passionate and interested in quantum materials. 

“I think the students here are very helpful, and they have very fresh minds that give me very interesting ideas,” he said.

Outside of the lab, Liu’s hobbies include raising tropical plants in a greenhouse he had built at his home.

“It is a hobby that I recently picked up, and I am really enjoying it. It forces me to slow down a little bit because with plants, you can’t rush it,” he said.