Quantum Interference and Spin Filtering Effects in Photo-responsive Endoperoxide Based Single Molecular Device

The development of stimuli responsive systems that can switch between two distinct spin states under the application of an external stimuli has always remained an illusory challenge. Here, we report a stimuli-based spin filter by utilizing photo-responsive endoperoxide (EPO) based single molecule device. The photo-irradiation on EPO triggers the homolytic cleavage of the peroxide O-O bond generating diradical intermediate centered on two O-atoms which facilitates high spin filtering efficiency when placed between gold electrodes. The broken conjugated scenario due to peroxide bridge of EPO hinders the propagation of de-Broglie waves across the molecular skeleton. While the diradical intermediate of EPO yields high conductance for one of the spin configuration. The transmission characteristics of various photoproducts along the photochemical reaction pathway of EPO are also investigated using density functional theory in combination with non-equilibrium Green’s function (NEGF-DFT) technique. We demonstrate the key role played by Quantum Interference (QI) effects in dramatic modulation of conductance arising due to different degree of conjugation along the reaction pathway of EPO.