Effects on the electronic and magnetic transitions by light in CdS/La_0.7Sr_0.3MnO₃ heterostructures

The strongly correlated material, La_0.7Sr_0.3MnO₃ (LSMO) exhibits a metal-to-insulator (MIT) coincidental with a magnetic transition near room temperature. Although the physical properties of LSMO can be manipulated by strain, chemical doping, temperature, or magnetic field, they often require large external stimuli. In order to add additional flexibility and tunability we developed a hybrid optoelectronic heterostructure, that uses photocarrier injection from cadmium sulfide (CdS) to an LSMO layer to change its electrical conductivity. Although LSMO exhibits no significant optical response, our ultra-thin CdS/LSMO heterostructures show an enhanced conductivity, with ~ 37 % resistance drop, at the transition temperature under light stimuli. This enhanced conductivity in response to light is comparable to the effect a 9 T magnetic field in pure LSMO. Surprisingly, the optical and magnetic responses of our heterostructures showed different effects when both stimuli are applied. This shows that incorporation of quantum materials into heterostructure may provide the means to add new functionalities.