Absorption of light dark matter in semiconductors

Understand

Semiconductors are by now well-established targets for direct detection of MeV to GeV dark matter via scattering off electrons.

• We show that semiconductor targets can also detect significantly lighter dark matter via an absorption process.
• When the dark matter mass is above the band gap of the semiconductor (around an eV), absorption proceeds by excitation of an electron into the conduction band.
• Below the band gap, multi-phonon excitations enable absorption of dark matter in the 0.01 eV to eV mass range.