Volatile and Non-volatile insulating state assisted by photoreaction on the hybrid CdS/Nickelates*

Rare-earth nickelates host a complex entanglement of various degrees of freedoms which offers a high tunability over several emerging noble phases, realizing a perfect playground for developing hybridized functionalities. Among these nickelates, the PrNiO₃ (PNO) possess a sharp metal to insulator transition (MIT) at ~120K concomitant with paramagnetic (PM) to antiferromagnetic (AFM) phase transition. These transitions are highly tunable upon application of substrate induced strain and growth symmetry. Here we study PNO thin films grown on NdGaO₃ substrate with two different orthorhombic crystal plane orientation, i.e., (101) and (110); PNO(101) and PNO(110), respectively. The optical functionalities of these films are realized with engineering photoconductor (CdS)/PNO hybrid Bi-layers. Depending on the growth symmetry CdS/PNO(101) and CdS/PNO(110) films exhibit two very different low temperature photoinduced non-volatile and volatile changes in the resistivity, respectively. The photoinduced non-volatile state is highly stable and stays intact over 10 hours. We assume that at low temperature AFM insulating phase of PNO, the light induced chemical reactions and photodoping is highly influenced by the direction of spin order which is along orthorhombic (101) direction.