A team led by Columbia University physicist Dmitri Basov has demonstrated that placing a thin crystal of hexagonal boron nitride on top of a molecular superconductor is enough to kill superconductivity near the shared interface, with no lasers, no electric fields, and no external power required. The finding, published in Nature in February 2026, challenges long-held assumptions about how fragile or controllable the superconducting state really is and opens a new route for switching quantum materials on and off through passive vibrational coupling alone.
A Thin Crystal That Shuts Down Zero Resistance
The experiment centered on a well-known organic superconductor with the shorthand name kappa-ET, formally designated kappa-(BEDT-TTF)2Cu[N(CN)2]Br. This material enters its superconducting state below a critical temperature near 11.5 K, at which point it expels magnetic fields through the Meissner effect and conducts electricity without resistance. When the researchers placed a thin flake of hexagonal boron nitride (hBN) directly on the kappa-ET surface, they observed a sharp drop in the Meissner response and superfluid density in the region closest to the interface. The suppression was not subtle: it registered clearly in standard magnetic measurements and extended some distance into the superconductor, indicating that the interfacial region had been pushed out of the superconducting state.
What makes the result striking is the simplicity of the setup. According to a Columbia-led summary, the experiment involved no external driving force or active tuning. The hBN flake was simply placed on the superconductor, and the suppression occurred passively. That distinguishes this work from earlier approaches that used intense laser pulses or microwave cavities to manipulate superconducting states. Here, the crystal itself did the work, acting as a kind of natural antenna whose internal vibrations matched and disrupted the molecular motions that sustain superconductivity in kappa-ET. By carefully varying the thickness and placement of the hBN, the team could dial in how strongly the superconducting response was quenched, suggesting a new kind of “contactless” control knob for quantum phases.
Why Vibrations Matter for Superconductivity
The connection between molecular vibrations and superconductivity in kappa-ET materials has been building for years. A 2020 study in Physical Review X showed that mid-infrared excitation of a specific carbon–carbon double-bond stretching mode in the kappa-ET family could enhance superconducting signatures, establishing that resonant vibrational coupling acts as a meaningful control knob for the superconducting state. In that earlier work, researchers used ultrafast laser pulses to selectively excite the C=C stretch and observed transient strengthening of superconducting-like behavior, even above the equilibrium transition temperature. The new Nature paper flips the script. Instead of pumping energy into the vibration to help superconductivity, the hBN crystal’s own vibrational modes siphon coherence away from it.
The mechanism hinges on frequency matching at the interface. Hexagonal boron nitride is a natural hyperbolic material, meaning it supports deeply subwavelength, low-loss vibrational modes called phonon polaritons. These are hybrid excitations in which lattice vibrations couple tightly with electromagnetic fields, and in thin hBN flakes their frequencies can be tuned by adjusting the crystal’s thickness and geometry. When those polariton frequencies overlap with the C=C stretching mode that helps sustain superconductivity in kappa-ET, the two materials lock into a resonant exchange. In essence, the hBN acts as an efficient sink that drains energy and phase coherence from the crucial molecular vibration in the organic layer. As that vibration loses its ability to mediate coherent electron pairing, the zero-resistance state collapses in a region extending tens to hundreds of nanometers below the interface.
How hBN Acts as a Natural Cavity
Conventional cavity quantum electrodynamics experiments require precisely machined mirrors or engineered microwave resonators to confine electromagnetic modes and couple them to matter. The Columbia team’s approach sidesteps that hardware by using the intrinsic properties of a 2D crystal. Foundational research by Basov and collaborators, reported in earlier nanoscale optics work, showed that phonon polaritons in atomically thin hBN flakes are tunable and can confine light to volumes far below the diffraction limit. That property turns even a microscopic hBN crystal into a natural electromagnetic cavity, one that does not need external mirrors or feedback loops to shape the vibrational environment of a nearby material. Instead, the geometry and dielectric response of the flake itself define a set of tightly confined modes.
This is the conceptual leap that separates the new work from standard optical or microwave cavity experiments. The hBN flake reshapes the vibrational density of states at the interface purely through its own material characteristics, creating a kind of built-in resonator for lattice vibrations. Because the polariton modes are confined to deeply subwavelength scales, the coupling to nearby molecular vibrations is intense and highly local. The preprint describing the measurements provides extended discussion of how the spatial profile of superconductivity suppression maps onto the polariton confinement length, reinforcing that the effect is not a bulk thermal artifact but a genuine resonance-driven phenomenon. By comparing regions under the hBN to uncovered areas of the same crystal, the authors argue that the superconducting order parameter is selectively quenched where the vibrational environment has been most strongly modified.
Broader Stakes for Quantum Material Control
The result sits at the intersection of two fast-moving research fronts. One involves using cavities and structured electromagnetic environments to alter material properties, sometimes called cavity-altered materials science. The other concerns the role of specific phonon modes in sustaining or disrupting superconductivity. Separate research at Brookhaven National Laboratory and Stony Brook University has tracked how vibrations channel energy through superconducting crystals. As one team described it, “We call vibrations with specific frequencies ‘phonons,’ and their interactions with flowing electrons were our target,” according to Stony Brook researchers. That work focused on copper-oxide superconductors rather than organic ones, but it underscored how particular vibrational pathways can either support or hinder the flow of paired electrons, depending on how they are excited and how energy is redistributed.
Viewed against this backdrop, the hBN and kappa-ET interface experiment suggests that carefully engineered vibrational environments could become a general design tool for quantum materials. Rather than chemically modifying a superconductor or applying large magnetic fields, researchers might one day toggle superconductivity by placing different 2D crystals on top, each acting as a tailored vibrational cavity. Related studies on kagome metals have already shown that when electrons synchronize in patterned lattices, subtle changes to geometry and interactions can open or close electronic gaps. By analogy, the new work implies that “vibrational patterning” via passive overlayer crystals could be used to sculpt where superconductivity survives on a device, potentially enabling nanoscale superconducting circuits, switchable Josephson junctions, or hybrid platforms in which superconductivity coexists with magnetism or charge order in a spatially programmable way.
From Fundamental Curiosity to Potential Devices
For now, the hBN-induced suppression of superconductivity remains a fundamental discovery rather than a ready-made technology. The experiments were carried out at cryogenic temperatures, in carefully prepared organic crystals, and the degree of control required to tune the vibrational resonance is still the domain of specialized laboratories. Yet the underlying principle, that a passive, power-free overlayer can deterministically reshape a quantum ground state, has clear implications for device engineering. In principle, one could pattern different regions of a superconducting film with distinct 2D crystals, each selected to couple to different vibrational modes, and thereby write a map of superconducting and nonsuperconducting areas without ever etching or chemically altering the base material.
Future work will need to clarify how universal this mechanism is across families of superconductors and whether similar passive vibrational coupling can also enhance, rather than suppress, desired quantum phases. Because phonon polaritons in hBN are highly tunable, it may be possible to design thicknesses and geometries that push energy into pairing-favorable modes instead of draining it away. More broadly, the experiment adds weight to a growing view that controlling the vibrational and electromagnetic environment—through natural cavities like hBN, through nanostructured substrates, or through engineered resonators—can be as powerful as changing a material’s chemistry. As researchers test these ideas in other correlated systems, the simple act of placing one crystal on another may emerge as a surprisingly versatile way to switch quantum matter on and off.
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*This article was researched with the help of AI, with human editors creating the final content.
