Dark matter is everywhere. It makes up 85 percent of all the matter in the universe, yet scientists still have no idea what it actually is. Now, researchers at Rice University in Houston have designed a new tool that could help solve one of the biggest mysteries in science.
The device is called SQWARE, short for Semiconductor Quantum Well Axion Radiometer Experiment. It uses ordinary semiconductor materials—the same kind found in computer chips and solar panels—to search for particles called axions, which scientists believe could be the building blocks of dark matter.
Jaanita Mehrani, a doctoral student at Rice University who led the study, explained the key innovation: unlike other dark matter detectors that need complex mechanical parts to work, SQWARE tunes itself simply by changing its position within a magnetic field.
"We are proposing a well-studied material from condensed matter physics for a new application—axion detection," Mehrani said. "What's different about this material is that it doesn't have to use complex mechanical tuning mechanisms, it simply tunes with the magnetic field."
The detector works by helping axions turn into light. Theory predicts that axions can convert into tiny particles of light called photons when exposed to a strong magnetic field—but the conversion is extremely weak. SQWARE uses stacks of ultrathin semiconductor layers called multiple quantum wells to trap electrons in flat, two-dimensional sheets. When trapped this way, the electrons behave like a plasma that gives photons an effective mass, making it easier for axions and photons to match up and convert into each other.
"We're trying to help that momentum mismatch and resonantly convert axions to photons, enhancing the photon signal so that we can more easily detect dark matter," Mehrani said.
The design was published in the journal Physical Review Letters. While the proposal is currently theoretical, the team built it with real-world constraints in mind, evaluating whether the semiconductor structures could be made using existing technology.
Associate Professor Shengxi Huang, a co-author on the study, noted that advances in semiconductor materials have opened doors far beyond their original uses. "This work explores whether those same materials can be adapted to address one of the central questions in particle physics and cosmology," she said.
The researchers are now testing actual semiconductor samples and building prototype devices to see if SQWARE performs as predicted in the lab.