Fig. 1: Electroresistance of α-Cu₂Se correlated with reversible switching of crystalline domains.

a TEM images of the boundary between the two domains (the green area marks the [10-1] domain) during the positive bias of 0–0.49 V, 0.56 V, 0.65 V, and 0.26 V, respectively. b TEM images of the boundary between the two domains during the negative bias of −0.44 V, −0.63 V, −0.32 V and −0.16 V, respectively. c, d the corresponding selected area electron diffraction patterns of α-Cu₂Se along the [0-10] and [10-1] directions, and illustrated atomic models of the two domains, respectively. e Current–voltage characteristics of Cu₂Se under the bias voltage. The insets show the enlarged view in the yellow dashed box. f Resistive-voltage characteristics change of α-Cu₂Se during the voltage cycle of 0-0.6-0-(−0.6)-0 V.