JERUSALEM, Sept. 15 (Xinhua) -- An international team of researchers has identified three unconventional materials that could improve the search for dark matter, according to Israel's Hebrew University of Jerusalem.
Dark matter is believed to make up around 85 percent of all matter in the universe. However, it has never been detected directly, although its gravitational influence shapes galaxies and the large-scale structure of the universe.
The new study, published in Physical Review Letters, examined titanium diselenide, strontium ruthenate, and hole-doped diamond, three unconventional materials whose unique electronic properties could serve as exceptionally sensitive dark matter detectors.
Unlike ordinary matter, dark matter does not emit, absorb, or reflect light, so it cannot be seen directly. The only way to look for it so far is to detect the very small amounts of energy released when dark matter particles interact with ordinary matter. This is more difficult for light dark matter, because the collisions are extremely faint and demand detectors sensitive enough to register tiny energy deposits.
The three materials in the study have low-energy collective electronic excitations, allowing them to respond more strongly to the minute energy transfer from light dark matter particles.
The study finds detectors based on titanium diselenide showed the strongest results, potentially improving sensitivity by two to three orders of magnitude (about 100 to 1,000 times) compared with current materials.
Two of the materials can also reveal the direction from which dark matter particles arrive, allowing researchers to distinguish genuine dark matter events from background noise.
The researchers said all three materials are practical candidates for future experiments as they can be synthesized using existing techniques, forming the basis of a new generation of dark matter experiments. ■
