For the first time, physicists have demonstrated that a material's superconductivity can be altered by coupling it to an in-built, light-confining cavity. In experiments published in Nature, a team led by Itai Keren at Columbia University show how quantum properties can be deliberately engineered by bonding carefully chosen materials together—without applying any external light, pressure, or magnetic field.
As researchers have probed the quantum behavior of solids in ever greater detail, they have uncovered a wealth of so-called "emergent" properties, which arise from intricate interactions between electrons, quantum spins, and localized vibrations of a crystal lattice. Phenomena including superconductivity, magnetism, and charge ordering all emerge from these kinds of collective effects—all richer and more complex than the sum of their microscopic parts.
Building on this principle, physicists are increasingly exploring whether materials could be designed with specific emergent behaviors built directly into their structures. Rather than tuning a compound after it is made, the goal here is to engineer its quantum environment from the outset.
In their study, Keren and colleagues investigated whether a material's quantum properties could be altered by hosting its own photonic cavity. In conventional systems, cavities are typically formed from two opposing mirrors that cause light to bounce back and forth. By carefully adjusting the spacing between the mirrors, researchers can trap light at selected frequencies, creating a resonant electromagnetic mode.
To realize an intrinsic version of such a cavity, the team began with a thin crystal of hexagonal boron nitride (hBN): stacks of atom-thick sheets, held together by weak van der Waals forces. Within certain infrared frequency ranges, light traveling parallel to the layers couples strongly to vibrations of the atomic lattice. This creates a hybrid light–matter excitation that becomes tightly confined inside the slab, effectively turning the hBN into a built-in infrared cavity.
The researchers then placed this hBN sheet onto a molecular superconductor: a compound composed of large, carbon-based molecules arranged in conducting layers. Within each molecule, carbon–carbon double bonds naturally vibrate at infrared frequencies, and these vibrations are known to play an active role in the emergence of superconductivity.
When the two materials were brought into contact, the infrared modes of the superconductor resonantly coupled to the confined modes of the hBN cavity, reshaping the local electromagnetic environment at their interface. As a result, the superconductor's superfluid density was markedly suppressed—even in complete darkness, without any external laser illumination.
This behavior contrasts sharply with most quantum materials studied so far, whose exotic properties typically require changes in chemical composition or external tuning through temperature, pressure, or magnetic fields.
By demonstrating that superconductivity can be modified simply by bonding a material to another structure with an in-built electromagnetic cavity, Keren's team provides compelling evidence that quantum ground states can be engineered through their surrounding vacuum environment.
The findings could open new routes towards advanced materials whose quantum properties are fine-tuned at the design stage, without the need to continuously manipulate their external conditions.
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Itai Keren et al, Cavity-altered superconductivity, Nature (2026). DOI: 10.1038/s41586-025-10062-6
Citation: Superconductivity controlled by a built-in light-confining cavity (2026, March 8) retrieved 10 March 2026 from https://phys.org/news/2026-02-superconductivity-built-confining-cavity.html
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