Theoretical study of ultrafast spin dynamics in a Co-Fe molecular Prussian blue analog and spin logic functionality design

Co-Fe Prussian blue analog (PBA) complex possesses various spin configurations and discrete energy levels with different types of spin localizations, making it suitable for the exploration of spin manipulation and logic functionality towards the molecular spintronics applications. In this paper, we perform an ab initio investigation on the electronic structure, spin localization, ultrafast optical-driven spin dynamics, and the possible spin logic functionality of this structure. The results show that within the calculated energy window of the many-body electronic states, spin-crossover and spin-transfer scenarios, driven by specific well-tailored laser, can be both achieved reversibly in subpicoseconds with high fidelities. Among them, a multifunctional dynamical process that simultaneously includes spin transfer, spin-crossover, and charge transfer is found. In addition, the potential of applying the same laser to drive different kinds of spin dynamics is indicated. Towards the device applications, the Pauli and Hadamard quantum logic gates and the half-adder functionality are further elaborately constructed based on the achieved spin scenarios. Our results suggest the present structure is quite promising in novel high-performance single-molecular devices and advanced spin logic processing from the viewpoints of both scientific research and technological applications, and thus propel the development of future molecular spintronic devices and quantum information technology.