First search for light fermionic dark matter absorption on electrons using germanium detector in CDEX-10 experiment

We present the first results of the search for sub-MeV fermionic dark matter absorbed by electron targets of germanium using the 205.4~kg$\cdot$day data collected by the CDEX-10 experiment, with the analysis threshold of 160~eVee. No significant dark matter (DM) signals over the background are observed. Results are presented as limits on the cross section of DM–electron interaction. We present new constraints of cross section in the DM range of 0.1–10 keV/$c^2$ for vector and axial-vector interaction. The upper limit on the cross section is set to be $6.8\times {10}^{-46}\mathrm{c}{\mathrm{m}}^2$ for vector interaction, and $2.3\times {10}^{-46}\mathrm{c}{\mathrm{m}}^2$ for axial-vector interaction at DM mass of 5 keV/$c^2$.