Yazdani wins APS Award for visualizing complex quantum states of matter

/by Allison Gasparini

Physicist Ali Yazdani has been awarded the 2023 APS Oliver E. Buckley Condensed Matter Physics Prize for “innovative applications of scanning tunneling microscopy and spectroscopy to complex quantum states of matter.”

“I feel humbled to receive the Oliver Buckley prize,” said Yazdani, Princeton’s Class of 1909 Physics Professor and director of the Princeton Center for Complex Materials. “Past winners have been some of the giants in the field.”

Yazdani shares the prize with his colleague, physicist J.C. Séamus Davis of Oxford University in the United Kingdom and University of Cork in Ireland.

“Ali is a true leader, in more than one way. He is blazing the trail in high resolution quantum microscopy and spectroscopy and in applying these tools to make new discoveries about fundamental properties of quantum states of matter,” said Herman Verlinde, the Class of 1909 Professor of Physics and chair of the Department of Physics. “With Séamus Davis, he has opened a whole new experimental field that has enriched our understanding of how interactions between atoms and electrons give rise to an enormously rich landscape of quantum phenomena. I have always felt proud and fortunate to have Ali as a colleague.”

The American Physical Society’s Oliver E. Buckley Condensed Matter Physics Prize, recognizes outstanding theoretical or experimental contributions to condensed matter physics. In bestowing the award, the society recognized the advances of Davis and Yazdani in studying novel quantum phases in materials with atomic resolution.

In particular, Yazdani was the first to visualize directly the signature of Majorana zero modes, an exotic state of matter predicted by quantum mechanics, with a scanning tunneling microscope. Unlike a regular microscope, a scanning tunneling microscope is not one that a researcher looks through with their eye. Instead, the microscope has a sharp metallic tip that is brought near to the surface of the material being studied. Using a quantum mechanical process, the microscope can probe the material’s wave function, a mathematical description of its quantum state.

Over his last nearly two decades at Princeton, Yazdani and his research team have been working on developing higher resolution instrumentation and techniques to understand the nature of many different quantum materials.

“With the advances in experimental techniques pioneered by Yazdani and Davis, we have seen that different parts of the surface of a crystal can be in patches of different states,” said F. Duncan Haldane, the Sherman Fairchild University Professor of Physics at Princeton and a winner of the 2016 Nobel Prize in Physics. “In the future, we can use the insights gained to build new and useful states of quantum matter, which potentially could become part of what many are calling the ongoing ‘second quantum revolution.’”

Yazdani was born and raised in Tehran, Iran, before immigrating to the United States and obtaining his bachelor’s degree in physics from the University of California, Berkeley. He went on to complete his Ph.D. in applied physics at Stanford University, where he first began working on superconductivity. As a postdoctoral scientist, Yazdani worked at Almaden, IBM Research’s Silicon Valley innovation lab.

After leaving IBM, he became a junior faculty member at the University of Illinois and built his first microscope for imaging materials at the atomic scale. In 2005, Yazdani moved to Princeton, and in 2015 was named Class of 1909 Professor of Physics. He has been named a fellow of the American Academy of Arts and Sciences, the American Association for the Advancement of Science, and APS. In 2019, he was named a member of the National Academies of Sciences.

“All the work leading up to this award was done by several generations of graduate students and postdoctoral collaborators that have been part of my research team,” said Yazdani. “It is really their hard work that is being recognized.”

“As a theorist, I have always felt a sense of privilege in working with Ali,” said Andrei Bernevig, a fellow professor of physics at Princeton and frequent collaborator. “He has a flair for the important questions in quantum materials. He challenges theorists to provide him with the right answers and explanations for his experiments: from why Majorana end modes show up at the edge of his iron wires on lead superconductors, to the origin of correlated electron insulators in twisted bilayer graphene. Except for the fact that at the very end, remarkably, our explanation turns out to be exactly what he thought they would be in the very first place, and the reason why he devised exactly the right experiment to show it. I’ve always thought he could have been a brilliant theorist — I don’t know if we helped much! He has an amazing flair for what nature likes to do in the quantum world.”

Yazdani will receive a certificate from APS listing his contributions to the field and a $20,000 prize. The prize was initially endowed in 1952 by Bell Laboratories, Alcatel-Lucent and is co-sponsored by the HTC-VIA Group. It is named for former Bell Laboratories president Oliver E. Buckley.