Dark matter makes up most of the matter in the universe, yet scientists have never detected it directly. Now, researchers at the Hebrew University have identified three unconventional quantum materials that could dramatically boost the search for these elusive particles, paving the way for a new generation of ultra-sensitive dark matter detectors.

For decades, physicists have searched for dark matter, the invisible substance thought to make up roughly 85% of all matter in the universe. Although its gravitational influence shapes galaxies and the large-scale structure of the cosmos, dark matter has never been directly detected. Now, an international team has identified a new class of quantum materials that could dramatically improve the search for some of the lightest and most elusive forms of dark matter.

Published in Physical Review Letters, the study introduces three unconventional materials whose unique electronic properties could serve as exceptionally sensitive dark matter detectors, potentially surpassing existing detector designs by several orders of magnitude.

The research by Prof. Yonit Hochberg and Rotem Ovadia from the Hebrew University of Jerusalem, Dr. Dino Novko from the Institute of Physics in Croatia, and Prof. Antonio Politano of the University of L'Aquila. The work brings together expertise in particle physics, condensed matter physics, and materials science to tackle one of the greatest unanswered questions in modern science.

Unlike ordinary matter, dark matter does not emit, absorb, or reflect light, making it effectively invisible. Scientists can search for it only by looking for the tiny amounts of energy deposited when dark matter particles interact with ordinary materials. Detecting light dark matter is particularly challenging because these interactions are extraordinarily weak, requiring materials capable of sensing minuscule energy transfers.

The team identified three promising candidates—titanium diselenide (TiSe₂), strontium ruthenate (Sr₂RuO₄), and hole-doped diamond—whose quantum properties naturally amplify these tiny signals. Each material hosts low-energy collective electronic excitations known as plasmons, allowing them to respond much more strongly to the minute energy deposits expected from light dark matter particles than conventional detector materials.

Using advanced first-principles quantum mechanical simulations, the researchers calculated how each material would respond to potential dark matter interactions. Their results show that detectors built from these materials could probe previously inaccessible regions of dark matter parameter space, outperforming today's leading candidate materials across a wide range of particle masses. In particular, detectors based on titanium diselenide could improve sensitivity by as much as two to
three orders of magnitude compared with current benchmark materials.

The study also reveals another powerful advantage: two of the proposed materials exhibit directional sensitivity. Rather than responding identically to particles arriving from every direction, their signals depend on the orientation of the incoming dark matter particles relative to the crystal structure. As the Earth rotates, this would create a predictable daily modulation in the detector signal, providing researchers with a powerful way to distinguish genuine dark matter events from background noise.

Beyond their exceptional sensitivity, the materials are also practical candidates for future experiments. The researchers note that all three can be synthesized using existing techniques, with titanium diselenide particularly well suited for scalable production. Combined with existing low-threshold detector technologies, these materials could form the basis of a new generation of dark matter experiments.

"Dark matter remains one of the greatest mysteries in physics, and discovering its nature requires us to rethink not only the particles we are searching for, but also the materials we use to search for them," said the researchers. "By identifying quantum materials that naturally amplify the tiny signals expected from light dark matter, we've uncovered a promising new path toward experiments that are significantly more sensitive than those available today."

The researchers believe their findings extend beyond the three materials examined in this study. Many quantum materials host unexplored low-energy collective excitations that could prove equally powerful for future dark matter searches, opening a new interdisciplinary frontier at the intersection of particle physics, quantum materials, and detector technology.