An international team of scientists has done something chemistry has never seen before. IBM, working alongside researchers from the University of Manchester, Oxford University, ETH Zurich, EPFL, and the University of Regensburg, has created and characterized a molecule whose electrons travel through its structure in a corkscrew-like pattern, fundamentally altering its chemical behavior. The findings were published today in Science.
The molecule, known as C13Cl2, is the first experimental observation of what scientists call a half-Mobius electronic topology in a single molecule. To the researchers’ knowledge, nothing like it has ever been synthesized, observed, or even formally predicted. And proving why it behaves the way it does required something equally extraordinary – a quantum computer.
The whole thing started at IBM, where the molecule was assembled atom by atom from a custom precursor synthesized at Oxford. Working under ultra-high vacuum at near-absolute-zero temperatures, researchers used precisely calibrated voltage pulses to remove individual atoms one at a time. The result is an electronic structure that undergoes a 90-degree twist with each circuit through the molecule, requiring four complete loops to return to its starting phase. That is a topological property that has no counterpart anywhere in chemistry’s existing record.
What makes it even more interesting to folks who follow materials science is that this topology can be switched. The molecule can move reversibly between clockwise-twisted, counterclockwise-twisted, and untwisted states. That means electronic topology is not just a curiosity to be stumbled upon in nature – it can be deliberately engineered. That is a big deal.
“First, we designed a molecule we thought could be created, then we built it, and then we validated it and its exotic properties with a quantum computer,” said Alessandro Curioni, IBM Fellow and Director of IBM Research Zurich. He invoked physicist Richard Feynman’s decades-old vision of building a computer capable of best simulating quantum physics, calling this a step toward that dream.
The quantum computing angle here is not just a supporting role. Electrons within C13Cl2 interact in deeply entangled ways, each influencing the others simultaneously. Modeling that requires tracking every possible configuration of those interactions at once – something that causes computational demands to grow exponentially and can quickly overwhelm classical machines. A decade ago, researchers could exactly model 16 electrons classically. Today that number has crept to 18. Using IBM’s quantum computer, the team was able to explore 32 electrons.
Quantum computers can represent these systems directly rather than approximate them, because they operate according to the same quantum mechanical laws that govern electrons in molecules. In this case, that capability helped reveal helical molecular orbitals for electron attachment – a fingerprint of the half-Mobius topology – and exposed the mechanism behind the unusual structure: a helical pseudo-Jahn-Teller effect.
This is what IBM calls quantum-centric supercomputing, a workflow that integrates quantum processing units, CPUs, and GPUs, breaking complex problems into parts and routing them to whatever system handles each best. The results here suggest this approach can contribute genuine scientific insight rather than just benchmarking exercises.
“I’m really excited to be part of a project where quantum hardware does real science, not just demos,” said Dr. Jascha Repp, a professor of physics at the University of Regensburg and a co-author on the paper.
IBM’s history in this area runs deep. The scanning tunneling microscope, which was central to imaging the new molecule, was invented at IBM in 1981. That work earned IBM scientists Gerd Binnig and Heinrich Rohrer the Nobel Prize in Physics in 1986. In 1989, IBM developed the first reliable method for manipulating individual atoms. The company has been building on those techniques ever since, and this discovery is arguably their most exotic result yet.
For chemistry as a field, the takeaway is that topology is now a switchable degree of freedom, something that can be engineered rather than simply found. Dr. Igor Roncevic, a lecturer in computational and theoretical chemistry at Manchester and a co-author, compared this shift to the role spintronics played at the turn of the century, when electron spin became a new tool for controlling data storage. Topology, he argues, could do the same for controlling material properties.
Whether this leads to real-world applications in materials or medicine anytime soon remains to be seen, but the science itself is hard to argue with. IBM has not announced any specific commercial product tied to this discovery.
