Collaborative Research: Unraveling Chirality-Induced Anisotropic Spin Transport in Hybrid Organic-Inorganic Semiconductors

About This Grant

Nontechnical Summary Chirality is a geometric property of a material that lacks mirror image symmetry. For example, the left hand cannot be transformed into its mirror image, the right hand, by any combination of rotation and translation. This project investigates how structural chirality at the molecular level can be harnessed to control the quantum property of electrons known as spin, without relying on the movement of electrical charge. Spin-based electronics, or spintronics, offers compelling advantages by reducing power consumption and heat generation in devices used for data storage, sensing, and computing. This project investigates structural chirality in semiconductors made from organic and inorganic components, called hybrid semiconductors. By tailoring molecular and crystal structures to manipulate spin transport, investigators will enable new mechanisms for spin transport. These findings will offer a path toward compact, reconfigurable spintronic devices that function without containing magnetic elements. The project integrates research with education and outreach efforts. New course modules and research opportunities for undergraduate and graduate students that will provide students with accessible resources in emerging technologies and contribute to the development of the next-generation semiconductor workforce. Technical Summary The research investigates how molecular chirality—specifically, the handedness and orientation of organic cations—modulates spin transport in low-dimensional chiral hybrid organic-inorganic semiconductors composed of alternating molecular cations and metal halide octahedra. The central scientific hypothesis is that anisotropic spin absorption, where spin current is preferentially absorbed in one direction over another, is determined more by the orientation and strength of the molecular chiral axis than by the overall symmetry of the crystal. To test this, the research team will synthesize a library of chiral hybrid organic-inorganic semiconductors with tailored molecular chirality and tunable alignment between the chiral axis and the crystal screw axis. Using spin-pumping and ultrafast magneto-optical Kerr effect techniques, pure spin current will be injected into the hybrid semiconductors, and the anisotropic spin absorption will be characterized as a function of the angle between spin polarization and chiral axis. By systematically varying molecular structure and chirality, the researchers aim to reveal the correlation between the degree and orientation of chirality and spin absorption anisotropy. The project will also develop new chirality descriptors that can be used to correlate structural features with spintronic behavior. This project will not only advance the fundamental understanding of spin transport in non-magnetic materials, but also establish new design principles for functional spintronic components that are tunable, scalable, and energy-efficient. By integrating material synthesis, structural characterization, and spin transport measurements, this work pushes the frontiers of low-dimensional and hybrid materials, enabling tailored quantum functionalities through the control of structural chirality. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.