The twist that changed physics

Rutgers physicistEva Andreihas earned one of science’s highest honors for work that helped reveal how a slight twist between atom-thin materials can transform their electronic properties.Last month, the Kavli Prize committeenamedAndrei, Board of Governors Professor in the Department of Physics and Astronomy at Rutgers University, a 2026 laureate in nanoscience alongside Pablo Jarillo-Herrero of MIT and Allan MacDonald of the University of Texas at Austin. The award recognized their foundational contributions to the field of twistronics, which explores how twisting atom-thin materials can alter their electronic behavior.“We discovered that as the electrons scatter off these huge patterns, they completely change their properties,” Andrei toldIBM Thinkin an interview. “If you change the twist angle, the properties keep changing.”

The work emerged from experiments intended to answer a different question. The Rutgers physicist had been studying graphene, a sheet of carbon just one atom thick, using a custom-built scanning tunneling microscope. Inan accountpublished by the Kavli Prize, she recalls receiving samples that contained twisted graphene layers rather than the monolayer material her team expected.Those twisted layers createdmoiré patterns, large interference patterns formed when two atomic lattices overlap at a slight angle. Andrei wrote that scientists had observed such patterns for years, but no one had examined how they affected electronic properties.Her team’s measurements revealed that small changes in angle could dramatically reshape graphene’s electronic structure. In her Kavli essay, Andrei writes that at a twist angle of 1.07 degrees, known as the “magic angle,” the electronic structure formed a so-called “flat band,” creating conditions for correlated electronic states.“All of a sudden, you have one material and you have many, many different properties,” she said. “They depend on how you dial in your battery.”Andrei said small changes in voltage could switch the material between different electronic states, including metallic, insulating and superconducting behavior.In the final paragraph of a 2009Nature Physicspaper, Andrei and her collaborators wrote that their findings opened opportunities to explore correlated electronic phases in graphene, in which electrons work together in ways that can produce unusual properties such as superconductivity.The road there was not always smooth.In her Kavli essay, the physicist described years spent building instruments from scratch and pursuing ideas that many researchers initially overlooked. One early graphene paper encountered fierce resistance during peer review, before eventually appearing inPhysical Review Letters. Another paper was rejected bySciencewithout peer review, only to be recognized later on by the magazine as one of the year’s top scientific breakthroughs.

Andrei said some of the most promising applications of twistronics could involvequantum computing.Quantum computers use quantum bits, orqubits, a unit of information that can exist in multiple states simultaneously. Researchers across academia and industry are pursuing different approaches to building more powerful quantum computers.“We can make a better qubit,” Andrei toldIBM Think. “We’re working on that now.”IBM has pursued quantum computing throughsuperconducting quantum processorsand a roadmap aimed atfault-tolerant quantum systems. Andrei said twisted materials could provide another path because researchers can tune their properties by changing voltage and twist angle.The Rutgers physicist pointed tosingle-photon detectorsas another potential application. Andrei said such detectors could be useful in computing systems and in transmitting and detecting information.In her Kavli essay, she writes that the 2018 discovery of superconductivity in magic-angle twisted bilayer graphene by Jarillo-Herrero’s group at MIT “officially launched the twistronics revolution.”But she believes the field is still in its early days.“The most exciting ones are going to be the ones I cannot imagine and predict,” Andrei said. “The best applications are the ones that I cannot imagine yet.”