Physicists Discover Key Agents in Flat Band Quantum Materials

Rice University and Weizmann Institute researchers visualize the building blocks of flat band quantum materials.

Mar. 21, 2026 at 10:07am

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In a study published in Nature Physics, researchers from Rice University and the Weizmann Institute collaborated to visualize the compact molecular orbitals that underlie the unusual quantum critical behavior in the flat band quantum material Ni3In. The findings provide new insights into high temperature superconductivity and open the door for new quantum applications.

Why it matters

Flat band quantum materials exhibit unique electronic properties due to destructive interference in electron motion, which is described by the mathematical concept of topology. Understanding the fundamental building blocks of these materials, known as compact molecular orbitals, could lead to breakthroughs in areas like high-temperature superconductivity and quantum computing.

The details

The researchers used atomic-scale spectroscopy to study the highly correlated metal Ni3In, which was selected for its potential practical applications. By probing the spatial profile of the current in Ni3In, they were able to reveal the kagome flat-band origin of its unusual quantum critical behavior and confirm the existence of the compact molecular orbitals predicted by Qimiao Si's theory.

  • The study was recently published in the journal Nature Physics.
  • The collaboration between researchers at Rice University and the Weizmann Institute began during their joint stay at the Kavli Institute of Theoretical Physics at UC Santa Barbara.

The players

Qimiao Si

The Harry C. and Olga K. Wiess Professor of Physics and Astronomy and director of Rice's Extreme Quantum Materials Alliance, who developed the theory that allowed him to ask how topology affects correlation physics in flat band materials.

Mounica Mahankali

A graduate student and co-first author on the paper, who contributed to the research.

Haim Beidenkopf

A professor at the Weizmann Institute in Israel, who specializes in imaging quantum materials using atomic resolution spectrometers and led the experimental work.

Ni3In

A highly correlated metal selected for the study due to its potential practical applications, as resolving the mechanism for its unusual electronic properties could provide insights into high-temperature superconductivity.

Kavli Institute of Theoretical Physics

The institution where the collaboration between the Rice University and Weizmann Institute researchers began during their joint stay.

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What they’re saying

“In flat band materials, electron motion experiences destructive interference.”

— Qimiao Si, Harry C. and Olga K. Wiess Professor of Physics and Astronomy, Rice University

“The electron motion is subject to a global effect described by the mathematical notion of topology. The electronic states are configured such that when one goes through the space of electron states and returns to the starting point, a nonzero winding number has been acquired.”

— Mounica Mahankali, Graduate student, Rice University

“In this study, we combined atomic-scale spectroscopy with material-specific analytical modeling to probe the spatial profile of the current that goes in and out of the kagome metal Ni3In. By doing so, we have revealed the kagome flat-band origin of the unusual quantum critical behavior in this compound and demonstrate the exquisite spatial profile expected from the compact molecular orbitals that leads to it.”

— Haim Beidenkopf, Professor, Weizmann Institute

What’s next

The researchers plan to continue exploring the role of compact molecular orbitals in flat band quantum materials, with the goal of unlocking new insights into high-temperature superconductivity and developing novel quantum applications.

The takeaway

This collaboration has provided experimental confirmation of the compact molecular orbitals predicted by theory, which serve as the fundamental building blocks underlying the unusual quantum critical behavior in flat band materials. These findings open up new avenues for research into exotic quantum phenomena and their potential technological applications.