Spin Hall effect in organic semiconductors

The spin Hall effect (SHE) achieves the conversion between charge current and spin current mediated by spin-orbit coupling (SOC), which has drawn considerable interest in spintronics. Organic semiconductors have emerged as promising candidates in spintronics due to their merits of flexibility, low cost, and long spin-relaxation times. In spite of the challenge from weak SOC in organics, the adjustable SOC, strong electron-lattice interaction, and structural anisotropy bring opportunities and new physics for a sizable organic SHE. This review presents an overview of experimental and theoretical advances in the SHE of organic semiconductors. On the experimental side, we introduce the measurable spin-charge conversion signals in a variety of organic semiconductors via inverse SHE measurements. On the theoretical side, we discuss several works on the microscopic mechanism of the organic SHE based on different transport theories. We particularly focus on the dynamical simulations in the framework of coupled organic polymer chains, where the microscopic dynamical pictures of the organic SHE are revealed by addressing the intrinsic structural properties of organic polymers.