Fig. 1: The potential profile for a CISS device with charge trapping.

a The charge trapping center (localized defect) is indicated by the dashed red circle in the molecular layer. If the electron is trapped there, it remains a metastable state even at zero bias (V_bias), like a nonvolatile memory device. Such a memory effect cannot be captured by the charge accumulation model in ref. ². Red and blue lines represent the potential of trapped and un-trapped states, respectively. b, c The charge trapping significantly modifies the tunneling barrier across the insulating molecular layer at finite bias. For example, the electron tunneling barrier is always higher in the electron trapped case, intendent from the bias direction. d Illustration of the CISS resistance (R) hysteresis between charge trapped and detrapped states, as a memory switched by the magnetic field (B).