Cornell Physicists Slide Graphene Layers With Voltage to Flip Magnetism On and Off
The Nature Nanotechnology study finds the magnetic state persists after the voltage is removed, hinting at rewritable quantum materials.
Physicists at Cornell have found that applying a voltage to a stack of four graphene layers can make the layers slide into a new arrangement, switching the material between nonmagnetic and magnetic states that stay put even after the voltage is turned off. The study was published Oct. 14 in Nature Nanotechnology.
The team works in the lab of Kenji Yasuda, an assistant professor in the School of Applied and Engineering Physics at Cornell Duffield College of Engineering. Doctoral student Daniel Brandon is the lead author. They studied graphene, a one-atom-thick sheet of carbon atoms arranged in a hexagonal pattern, stacked four layers deep.
A material's properties depend not only on which atoms it contains but on how they are arranged. Graphite and diamond are both pure carbon, yet they differ wildly in color, strength, transparency and conductivity. Changing a material's structure normally means breaking strong chemical bonds and rebuilding them, which is slow and energy-intensive and often requires high pressure and temperature.
The Cornell group went after something gentler. "We discovered that if we focus on the much weaker bonds between the layers, known as van der Waals bonds, we were able to reconfigure the crystal structure," Yasuda said. By applying voltage, they shifted the alignment of the layers, a process called sliding, and changed how the graphene was stacked.
The most stable and common pattern, the Bernal configuration, corresponds to a nonmagnetic state. Voltage pushed the stack into the rarer and less stable rhombohedral configuration, a state associated with magnetism, superconductivity and other exotic quantum phenomena. The material could be flipped back and forth between the two.
"One of the things that makes this sliding technique interesting is that it is nonvolatile, meaning that the act of sliding and physically moving atoms creates a reliable memory source," Brandon said. "Once the material is in that state, it persists for a long time and it can go back and forth between the two fairly consistently."
Yasuda said the ability to rewrite a crystal's structure electrically opens a broader door. "This provides a fundamentally new way to control matter," he said. "By electrically rewriting the structure, we may be able to switch not only magnetism, but also superconductivity and other quantum states, opening a path toward reconfigurable quantum materials and new forms of nonvolatile memory." Co-authors include researchers from Stanford University, Stony Brook University and Japan's National Institute for Materials Science. The paper is "Gate-induced layer sliding drives non-volatile switching of magnetism in tetralayer graphene," DOI 10.1038/s41565-026-02306-x.
