Origins of Structural and Electronic Chirality in the 2D Hybrid Perovskites

Abstract

Chirality has long been regarded as a fundamental property in physics, chemistry, and biology. The recent observation of spin-polarized electrons in 2D chiral organic–inorganic hybrid perovskites has attracted significant attention, presenting promising applications and profound implications for fundamental science. However, unresolved issues in this field, such as the mechanisms of chiral transfer and the origins of chiral activity regulation, remain elusive. Here, it is found that the formation of polarized orbitals originated from introduction of chiral molecules capture the essence of chirality in the perovskites. Under the action of local polarization fields and spin-orbit coupling (SOC), the locking between electron spin and orbital angular momentum (OAM) in chiral perovskites constitutes a novel topological electronic state. Moreover, the electron density difference driven by the polarized orbitals leads us to propose a new simulation method for evaluating the strength of chirality in 2D chiral perovskites (c-OIHPs). Ultimately, a simple descriptor is constructed to quantitatively reveal the fundamental causes of chiral behavior. Remarkably, the descriptor not only reveals the impact factors of chirality strength, namely, Δβin (the same as momentum offset k0), ΔE (energy splitting), and Lz (OAM) at the CB, but also overcomes the limitation of traditional methods that must rely on experiments. By combining emerging concepts with established conclusions, a comprehensive perspective is presented that highlights the interplay between chirality, OAM-spin locking, and polarized orbitals and pave the way for designing future devices integrating chiroptical and spin-dependent properties.