Peng Xiong

Low‐dimensional (LD) organic metal halide hybrids (OMHHs) have attracted widespread attention owing to their exceptional structural versatility and emergent photophysical and spin‐dependent properties. While hundreds of LD OMHHs have been reported to date, systematic investigations into how organic cations influence structural dimensionality and magnetic behavior remain limited. Here, we report a steric‐engineering strategy to control structural dimensionality and magnetism in LD OMHHs. By systematically tuning methyl substitution in 1,3‐propanediamine (PDA), we achieve a structural progression from two‐dimensional (2D) Dion‐Jacobson (DJ) and Ruddlesden‐Popper (RP) phases to a mixed one‐dimensional/zero‐dimensional (1D/0D) structure, and ultimately isolated 0D structures in a series of organic copper(II) chloride hybrids. This structural evolution modulates magnetic exchange pathways, giving rise to coexisting ferromagnetic (FM) and antiferromagnetic (AFM) interactions in 2D OMHHs, dual AFM transitions in the mixed‐dimensional (MD) system, and paramagnetic (PM) behavior in 0D compounds. Density functional theory (DFT) calculations reveal spin configurations consistent with experimentally observed magnetic behavior. This work presents a unique approach to precisely controlling the dimensionality and magnetism of OMHHs, paving the way for the rational design of ionically bonded organic–inorganic hybrid materials for spintronic applications.

Mixed‐dimensional (MD) organic–metal halide hybrids (OMHHs) provide an emerging platform for integrating distinct structure‐dependent optical and magnetic behaviors within a single crystalline phase. While the photophysical properties of conventional low‐dimensional (LD) OMHHs have been widely studied, organic–inorganic hybrids that combine multiple molecular‐level dimensionalities remain largely underexplored. Here, we report a structurally unique MD diammonium manganese(II) bromide hybrid, (TMPDA) ₃ (Mn ₂ Br ₆ )(MnBr ₄ ) ₂ (TMPDA = N,N,N′,N′‐tetramethyl‐1,3‐propanediammonium), which simultaneously incorporates one‐dimensional (1D) [Mn ₂ Br ₆ ²⁻ ] _∞ chains and zero‐dimensional (0D) MnBr ₄ ²⁻ tetrahedra within a single crystalline framework. This architecture enables two optical centers to coexist in the same material, yielding excitation‐dependent dual emissions from both the 1D chains and 0D tetrahedra with high photoluminescence quantum efficiencies (PLQEs) of up to 62%. Magnetic measurements reveal weak antiferromagnetic interactions along the 1D chains, arising from Mn···Mn superexchange mediated by bridging bromides. These findings highlight the opportunities offered by MD OMHHs to expand structural and functional tunability beyond traditional LD hybrids, opening new directions for designing multifunctional materials with coupled optical and magnetic properties.

Hybrid metal halides have transformed optoelectronics, yet predictive synthesis remains elusive beyond the perovskite family, to which the Goldschmidt tolerance factor offers guidance. Here, we present an open-source platform (https://apollo-omhh.com) that integrates a density functional theory (DFT) database of 7,439 organic metal halide hybrids (OMHHs), derived from 118 experimentally reported compounds spanning diverse electronic structures. Leveraging this dataset and remanent stability theory, we introduce a predictive framework to assess OMHH synthesizability. This framework successfully guided the experimental synthesis of eight previously unreported compounds and achieved 85.2% prediction accuracy across 27 synthesis attempts. This framework is further extended to predict 268 synthesizable OMHHs among 1144 examined OMHHs. Together, these advances establish a data-driven foundation for accelerating the discovery and rational design of hybrid materials beyond perovskite structures.

The actomyosin complex—nature’s dynamic engine composed of actin filaments and myosin motors—is emerging as a versatile tool for bio-integrated nanotechnology. This review explores the growing potential of actomyosin-powered systems in biosensing and actuation applications, highlighting their compatibility with physiological conditions, responsiveness to biochemical and physical cues and modular adaptability. We begin with a comparative overview of natural and synthetic nanomachines, positioning actomyosin as a uniquely scalable and biocompatible platform. We then discuss experimental advances in controlling actomyosin activity through ATP, calcium, heat, light and electric fields, as well as their integration into in vitro motility assays, soft robotics and neural interface systems. Emphasis is placed on longstanding efforts to harness actomyosin as a biosensing element—capable of converting chemical or environmental signals into measurable mechanical or electrical outputs that can be used to provide valuable clinical and basic science information such as functional consequences of disease-associated genetic variants in cardiovascular genes. We also highlight engineering challenges such as stability, spatial control and upscaling, and examine speculative future directions, including emotion-responsive nanodevices. By bridging cell biology and bioengineering, actomyosin-based systems offer promising avenues for real-time sensing, diagnostics and therapeutic feedback in next-generation biosensors.

Introducing the concept of topology into material science has sparked a revolution from classic electronic and optoelectronic devices to topological quantum devices. The latter has potential for transferring energy and information with unprecedented efficiency. Here, we demonstrate a topological diode effect on the surface of a three-dimensional material, SmB 6 , a candidate topological Kondo insulator. The diode effect is evidenced by pronounced rectification and photogalvanic effects under electromagnetic modulation and radiation at radio frequency. Our experimental results and modeling suggest that these prominent effects are intimately tied to the spatially inhomogeneous formation of topological surface states (TSS) at the intermediate temperature. This work provides a manner of breaking the mirror symmetry (in addition to the inversion symmetry), resulting in the formation of pn -junctions between puddles of metallic TSS. This effect paves the way for efficient current rectifiers or energy-harvesting devices working down to radio frequency range at low temperature, which could be extended to high temperatures using other topological insulators with large bulk gap.

Electrical generation and transduction of polarized electron spins in semiconductors (SCs) are of central interest in spintronics and quantum information science. While spin generation in SCs is frequently realized via electrical injection from a ferromagnet (FM), there are significant advantages in nonmagnetic pathways of creating spin polarization. One such pathway exploits the interplay of electron spin with chirality in electronic structures or real space. Here, utilizing chirality‐induced spin selectivity (CISS), the efficient creation of spin accumulation in n‐doped GaAs via electric current injection from a normal metal (Au) electrode through a self‐assembled monolayer (SAM) of chiral molecules (α‐helix l‐polyalanine, AHPA‐L), is demonstrated. The resulting spin polarization is detected as a Hanle effect in the n‐GaAs, which is found to obey a distinct universal scaling with temperature and bias current consistent with chirality‐induced spin accumulation. The experiment constitutes a definitive observation of CISS in a fully nonmagnetic device structure and demonstration of its ability to generate spin accumulation in a conventional SC. The results thus place key constraints on the physical mechanism of CISS and present a new scheme for magnet‐free SC spintronics.

Electrical generation and transduction of polarized electron spins in semiconductors are of central interest in spintronics and quantum information science. While spin generation in semiconductors has been frequently realized via electrical injection from a ferromagnet, there are significant advantages in nonmagnetic pathways of creating spin polarization. One such pathway exploits the interplay of electron spin with chirality in electronic structures or real space. Here, utilizing chirality-induced spin selectivity (CISS), we demonstrate efficient creation of spin accumulation in n-doped GaAs via electric current injection from a normal metal (Au) electrode through a self-assembled monolayer of chiral molecules (α-helix L-polyalanine, AHPA-L). The resulting spin polarization is detected as a Hanle effect in the n-GaAs, which is found to obey a distinct universal scaling with temperature and bias current consistent with chirality-induced spin accumulation. The experiment constitutes a definitive observation of CISS in a fully nonmagnetic device structure and demonstration of its ability to generate spin accumulation in a conventional semiconductor. The results thus place key constraints on the physical mechanism of CISS and present a new scheme for magnet-free semiconductor spintronics.

Chirality has been a property of central importance in physics, chemistry and biology for more than a century. Recently, electrons were found to become spin polarized after transmitting through chiral molecules, crystals, and their hybrids. This phenomenon, called chirality-induced spin selectivity (CISS), presents broad application potentials and far-reaching fundamental implications involving intricate interplays among structural chirality, topological states, and electronic spin and orbitals. However, the microscopic picture of how chiral geometry influences electronic spin remains elusive, given the negligible spin-orbit coupling (SOC) in organic molecules. In this work, we address this issue via a direct comparison of magnetoconductance (MC) measurements on magnetic semiconductor-based chiral molecular spin valves with normal metal electrodes of contrasting SOC strengths. The experiment reveals that a heavy-metal electrode provides SOC to convert the orbital polarization induced by the chiral molecular structure to spin polarization. Our results illustrate the essential role of SOC in the metal electrode for the CISS spin valve effect. A tunneling model with a magnetochiral modulation of the potential barrier is shown to quantitatively account for the unusual transport behavior.