Detection of Super-light Dark Matter Using Graphene Sensor

We propose a new dark-matter detection strategy that will enable the search of super-light dark matter \(m_\chi \simeq 0.1\) keV, representing an improvement of the minimum detectable mass by more than three order of magnitude over the ongoing experiments. This is possible by integrating intimately the target material, \(\pi\)-bond electrons in graphene, into a Josephson junction to achieve a high sensitivity detector that can resolve a small energy exchange from dark matter as low as \(\sim 0.1\) meV. We investigate detection prospects with pg-, ng-, and \(\mu\)g-scale detectors by calculating the scattering rate between dark matter and free electrons confined in two-dimensional graphene with Pauli-blocking factors included. We find not only that the proposed detector can serve as a complementary probe of super-light dark matter but also achieve higher experimental sensitivities than other proposed experiments, thanks to the extremely low energy threshold of our Josephson junction sensor.