The lack of standardized reporting and annotation of nucleic acid nanostructures limits reproducibility, interoperability and the efficient reuse of published designs. NanostarDB is a community-driven knowledgebase that standardizes nucleic acid nanostar designs through persistent identifiers, structural annotations, and integrated computational tools for design exploration, analysis and reuse, and is compliant with principles of findability, accessibility, interoprability and reusability (FAIR).
Two-dimensional (2D) ferroelectric semiconductors offer unique opportunities for ultrathin non-volatile memory and neuromorphic devices, yet the role of stacking order in intrinsic ferroelectric systems remains largely unexplored. Here we report the stacking-controlled growth of large-area 2D β′- and α-In2Se3 with distinct 2H and 3R configurations through chemical vapour deposition by regulating selenium kinetics and strain relaxation. By combining atomic-resolution microscopy, non-linear optical characterization and first-principles calculations, we uncover a strong correlation between stacking order and ferroelectric behaviour: β′-In2Se3 undergoes an antiferroelectric-to-paraelectric transition when switching from 2H to 3R stacking, whereas in α-In2Se3, in-plane ferroelectric polarization vanishes during the 3R-to-2H transition. We further achieve the controlled synthesis of 2H/3R ferroelectric homojunctions and directly visualize polarization-dependent interfacial potential barriers using differential phase-contrast scanning transmission electron microscopy. The engineered homojunctions exhibit switchable band alignment and tunable carrier transport, yielding memristors with significantly reduced switching voltages and an on/off ratio of ∼2.6 × 104, approximately one order of magnitude higher than devices based on single-stacking α-In2Se3. These findings establish stacking order as a powerful structural parameter for tailoring ferroelectricity in 2D materials and introduce stacking-engineered polymorphic heterogeneity as a versatile platform for high-performance ferroelectric electronics and memory technologies. Stacking-controllable 2D In2Se3 grown by chemical vapour deposition reveals a strong dependence of ferroelectricity on stacking order. A 2H/3R homojunction memristor achieves an on/off ratio one order of magnitude higher than that of pure-phase devices, offering opportunities for advanced ferroelectric memory applications.
Chemical ligation of polymer segments is an essential approach to extend the length of synthetic polymers. Ligating individual polymer chains at the molecular level remains a formidable challenge owing to the entropically disfavoured collision probability between reactive end groups, and the need to overcome the activation barrier. Here we report a pathway to chemical ligation of synthetic polymers via folding-driven supramolecular polymerization followed by dynamic covalent polycondensation. Our strategy, which does not require thermal activation, uses hydrogen bonds that induce conformational folding to rigidify the polymer backbone while providing sticky ends for supramolecular pre-organization. This promotes base-catalysed covalent exchange between terminal groups (in our case, thiolate–disulfide groups). We obtain mechanistic insight in the ligation process by engineering side-chain units that determine conformational foldability and intermolecular H-bonding pre-organization. The resulting extended helical polymers fold into hierarchical globular architectures in solution and exhibit thermo-responsive macromolecular entanglements in bulk films. The combination of noncovalent assembly and dynamic covalent polymerization offers a supramolecular pathway for non-thermal and controllable polycondensation of dynamic polymers with secondary structures. Chemical ligation of synthetic polymers is achieved via supramolecular polymerization followed by dynamic covalent polycondensation in a process that does not require thermal activation.
The widespread use of the term ‘battery’ has caused misunderstandings about what truly defines a battery. In this Comment, we critically examine the terminology and fundamental concepts of batteries to favour reliable interdisciplinary advancement of energy storage technology and research.
Layer stacking in two-dimensional materials can strongly impact electronic phases. In graphene, for instance, the metastable rhombohedral stacking arrangement hosts correlated and topological electronic phases, which are absent in conventional Bernal stacking. Here we use the sliding-induced first-order structural phase transition between Bernal and rhombohedral tetralayer graphene driven by gate voltages to manipulate the magnetic phase of the sample. Through transport measurement on marginally twisted double-bilayer graphene samples, we observe bistable switching between a Bernal-dominant state and a rhombohedral–Bernal mixed state across a wide space of the gate-voltage phase diagram. The structural phase transition induces a non-volatile switching between a non-magnetic and a ferromagnetic phase. We characterize the latter phase via low-temperature electric transport measurements and observe an anomalous Hall effect. The sign reversal of the anomalous Hall signal under opposite displacement fields suggests that the Hall signal may originate from domain boundaries between Bernal and rhombohedral regions. Our experiments showcase how gating-induced sliding phase transitions of two-dimensional materials can provide on-demand toggle switching between complex phases and offer insights on the effect of stacking domain boundaries on the global response of the system. Gate-voltage sweeps drive a first-order sliding transition between Bernal-dominant and rhombohedral–Bernal mixed stacking in marginally twisted double-bilayer graphene, which allows for non-volatile on/off switching of the low-temperature ferromagnetic phase.
