Pablo Jarillo-Herrero is one of 2026 Kavli Prize Awardees
The Norwegian Academy of Science and Letters has awarded the 2026 Kavli Prize in Nanoscience to Pablo Jarillo-Herrero — independent group leader at the Max Planck Institute for Solid State Research (MPI-FKF) — together with Eva Y. Andrei (Rutgers University) and Allan H. MacDonald (University of Texas at Austin). The three physicists share the prize "for foundational work that established the field of twistronics," and with it a gold medal and a one-million-dollar honorarium.
Condensed matter physics with a twist
The story begins in 2009. Eva Andrei and her group, studying graphene with scanning tunnelling microscopy, examined a sample that — by happy accident — had grown not as a single sheet but as two layers slightly rotated against each other. Under the microscope, the offset sheets produced a striking moiré pattern: a large-scale superlattice emerging from the imperfect overlap. The group recognized that small changes in the twist angle profoundly reshaped the electrons' behavior, slowing their motion dramatically. Geometry, not chemistry, was steering the material.
Two years later, in 2011, Allan MacDonald — together with Rafael Bistritzer — supplied the theory. Their calculations predicted that at a specific "magic angle" of roughly 1.1 degrees, the moiré superlattice would flatten the material's electronic bands almost entirely. In such flat bands, the electrons barely move: their kinetic energy is quenched, and the energy of their mutual repulsion comes to dominate instead. Strong interactions of this kind are precisely the breeding ground for exotic, collective electronic phases. The Bistritzer–MacDonald model became the theoretical bedrock of what are now called moiré materials.
For years the prediction outran the laboratory: stacking two atomic sheets and holding them aligned to within a fraction of a degree, cleanly enough to reveal the effect, proved fearsomely difficult. Then, in 2018, Pablo Jarillo-Herrero and his team at MIT succeeded. On 5 April 2018, Nature published two landmark papers from his group. At the magic angle, they reported, twisted bilayer graphene becomes a correlated insulator at "half-filling" of the flat band — electrons locked in place by their mutual repulsion, much as in a Mott insulator. Add or remove a few charges by electrostatic gating, and the very same device turns into an unconventional superconductor, carrying current without resistance up to a critical temperature of about 1.7 kelvin. Both phases — and the transition between them — are reached in one sample, simply by turning an electrostatic "knob".
That tunability is what makes the system so powerful. The superconductivity emerges at an extraordinarily low carrier density, around 10¹¹ electrons per square centimeter — orders of magnitude below conventional superconductors. This places twisted bilayer graphene among the most strongly coupled superconductors known, in the regime near the crossover between the two great pictures of superconductivity (the BCS and Bose–Einstein-condensate limits); its small Fermi surfaces even echo those of the underdoped cuprates.
The cuprates make the contrast vivid. These copper-oxide superconductors had challenged physicists for decades, yet mapping their phase diagram meant re-doping the chemistry for every data point — effectively a new sample for each measurement. Twisted bilayer graphene collapses that labour into a single, voltage-tuned device. As Jarillo-Herrero and his colleagues put it in Nature, twisted bilayer graphene is "a precisely tunable, purely carbon-based, two-dimensional superconductor." The phrase is worth unpacking. Precisely tunable means a single chip can be walked through insulating, superconducting and other correlated phases at will, just by adjusting a gate voltage. Purely carbon-based sets it apart from the chemically intricate copper-oxide and iron-based superconductors: here, all the richness comes from geometry, not composition. And two-dimensional makes every electron accessible at the surface, open to direct measurement and manipulation. Together these qualities make the material, as the authors argue, an ideal platform for probing strongly correlated physics — with implications reaching toward the unsolved mechanism of high-temperature superconductivity and toward quantum spin liquids, exotic states in which electron spins remain disordered and entangled even at the approach to absolute zero.
The laureate
Pablo Jarillo-Herrero earned his Licenciatura in physics at the University of Valencia in 1999, followed by a master's degree at the University of California, San Diego in 2001. He completed his PhD at Delft University of Technology in 2005 and, after a postdoctoral fellowship at Columbia University, joined MIT in 2008, where he is today the Cecil and Ida Green Professor of Physics. The Kavli Prize joins an already remarkable record, including the Oliver E. Buckley Prize — the most prestigious U.S. award in condensed matter physics — and the Wolf Prize in Physics, both received in 2020.
A second base in Stuttgart
Jarillo-Herrero's connection to the MPI-FKF runs through the 2021 Max Planck-Humboldt Research Award, which brought him to Stuttgart to build a research program in close cooperation with the University of Stuttgart. Here he leads the Ultra Cold 2D Quantum Matter group, hunting for the next generation of moiré systems. The work spans the full arc of the field he helped create: fabricating these delicate stacked structures with extreme precision, developing the "tuning knobs" that control their properties, and characterizing them by a range of methods — among them a technique that lets researchers watch, almost live, how the angle between two layers reshapes their electronic behavior.
