The existence of dark matter (DM) is established by overwhelming evidence in cosmological and astronomical observations. Possible interactions between dark matter (DM) particles and baryonic matter have been searched for in underground laboratories using ultra-low background detectors by directly detecting recoil signals. DM within a mass range between GeV/c2 to TeV/c2 have been mostly searched for via its elastic scattering off atomic nucleus. And sub-GeV light DM can scatter with shell electrons, which may subsequently produce sufficiently large ionization signals in the detector. Such DM-electron scatterings open up a new experimental paradigm. PandaX-II 2-phase liquid/gas xenon dark matter detector can probe this kind of signals to search for light DM. In this talk, constraints on light dark matter through its interactions with shell electrons in the PandaX-IIwith a total 46.9 tonneday exposure is reported. 1821 candidates are identified within ionization signal range between 50 to 75 photoelectrons, corresponding to a mean electronic recoil energy from 0.08 to 0.15~keV. We provide the world's most stringent limit within the dark matter mass range from 15 to 30MeV/c2, with the corresponding cross section from 2.5x10e-37 to 3.1x10e-38 cm2.
