Since their discovery in 1960(1), metallic glasses based on a wide range of elements have been developed(2). However, the theoretical prediction of glass-forming compositions is challenging and the discovery of alloys with specific properties has so far largely been the result of trial and error(3-8). Bulk metallic glasses can exhibit strength and elasticity surpassing those of conventional structural alloys(9-11), but the mechanical properties of these glasses are critically dependent on the glass transition temperature. At temperatures approaching the glass transition, bulk metallic glasses undergo plastic flow, resulting in a substantial decrease in quasi-static strength. Bulk metallic glasses with glass transition temperatures greater than 1,000 kelvin have been developed, but the supercooled liquid region (between the glass transition and the crystallization temperature) is narrow, resulting in very little thermoplastic formability, which limits their practical applicability. Here we report the design of iridium/nickel/tantalum metallic glasses (and others also containing boron) with a glass transition temperature of up to 1,162 kelvin and a supercooled liquid region of 136 kelvin that is wider than that of most existing metallic glasses(12). Our Ir-Ni-Ta-(B) glasses exhibit high strength at high temperatures compared to existing alloys: 3.7 gigapascals at 1,000 kelvin(9,13). Their glass-forming ability is characterized by a critical casting thickness of three millimetres, suggesting that small-scale components for applications at high temperatures or in harsh environments can readily be obtained by thermoplastic forming(14). To identify alloys of interest, we used a simplified combinatorial approach(6-8) harnessing a previously reported correlation between glass-forming ability and electrical resistivity(15-17). This method is non-destructive, allowing subsequent testing of a range of physical properties on the same library of samples. The practicality of our design and discovery approach, exemplified by the identification of high-strength, high-temperature bulk metallic glasses, bodes well for enabling the discovery of other glassy alloys with exciting properties.

Oxygen, one of the most abundant elements on Earth, often forms an undesired interstitial impurity or ceramic phase (such as an oxide particle) in metallic materials. Even when it adds strength, oxygen doping renders metals brittle(1-3). Here we show that oxygen can take the form of ordered oxygen complexes, a state in between oxide particles and frequently occurring random interstitials. Unlike traditional interstitial strengthening(4,5), such ordered interstitial complexes lead to unprecedented enhancement in both strength and ductility in compositionally complex solid solutions, the so-called high-entropy alloys (HEAs)(6-10). The tensile strength is enhanced (by 48.5 +/- 1.8 per cent) and ductility is substantially improved (by 95.2 +/- 8.1 per cent) when doping a model TiZrHfNb HEA with 2.0 atomic per cent oxygen, thus breaking the long-standing strength-ductility trade-off(11). The oxygen complexes are ordered nanoscale regions within the HEA characterized by (O, Zr, Ti)-rich atomic complexes whose formation is promoted by the existence of chemical short-range ordering among some of the substitutional matrix elements in the HEAs. Carbon has been reported to improve strength and ductility simultaneously in face-centred cubic HEAs(12), by lowering the stacking fault energy and increasing the lattice friction stress. By contrast, the ordered interstitial complexes described here change the dislocation shear mode from planar slip to wavy slip, and promote double cross-slip and thus dislocation multiplication through the formation of Frank-Read sources (a mechanism explaining the generation of multiple dislocations) during deformation. This ordered interstitial complex-mediated strain-hardening mechanism should be particularly useful in Ti-, Zr- and Hf-containing alloys, in which interstitial elements are highly undesirable owing to their embrittlement effects, and in alloys where tuning the stacking fault energy and exploiting athermal transformations(13) do not lead to property enhancement. These results provide insight into the role of interstitial solid solutions and associated ordering strengthening mechanisms in metallic materials.

Lightweight magnesium alloys are attractive as structural materials for improving energy efficiency in applications such as weight reduction of transportation vehicles. One major obstacle for widespread applications is the limited ductility of magnesium, which has been attributed to [Formula: see text] dislocations failing to accommodate plastic strain. We demonstrate, using in situ transmission electron microscope mechanical testing, that [Formula: see text] dislocations of various characters can accommodate considerable plasticity through gliding on pyramidal planes. We found that submicrometer-size magnesium samples exhibit high plasticity that is far greater than for their bulk counterparts. Small crystal size usually brings high stress, which in turn activates more [Formula: see text] dislocations in magnesium to accommodate plasticity, leading to both high strength and good plasticity.

Over the past decade, topological materials-in which the topology of electron bands in the bulk material leads to robust, unconventional surface states and electromagnetism-have attracted much attention. Although several theoretically proposed topological materials have been experimentally confirmed, extensive experimental exploration of topological properties, as well as applications in realistic devices, has been restricted by the lack of topological materials in which interference from trivial Fermi surface states is minimized. Here we apply our method of symmetry indicators to all suitable nonmagnetic compounds in all 230 possible space groups. A database search reveals thousands of candidate topological materials, of which we highlight 241 topological insulators and 142 topological crystalline insulators that have either noticeable full bandgaps or a considerable direct gap together with small trivial Fermi pockets. Furthermore, we list 692 topological semimetals that have band crossing points located near the Fermi level. These candidate materials open up the possibility of using topological materials in next-generation electronic devices.

The solid-electrolyte interphase (SEI) is probably the least understood component in Li-ion batteries. Considerable effort has been put into understanding its formation and electrochemistry under realistic battery conditions, but mechanistic insights have mostly been inferred indirectly. Here we show the formation of the SEI between a graphite anode and a carbonate electrolyte through combined atomic-scale microscopy and in situ and operando techniques. In particular, we weigh the graphitic anode during its initial lithiation process with an electrochemical quartz crystal microbalance, which unequivocally identifies lithium fluoride and lithium alkylcarbonates as the main chemical components at different potentials. In situ gas analysis confirms the preferential reduction of cyclic over acyclic carbonate molecules, making its reduction product the major component in the SEI. We find that SEI formation starts at graphite edge sites with dimerization of solvated Li(+) intercalation between graphite layers. We also show that this lithium salt, at least in its nascent form, can be re-oxidized, despite the general belief that an SEI is electrochemically inert and its formation irreversible.

Historically long accepted to be the singular root cause of capacity fading, transition metal dissolution has been reported to severely degrade the anode. However, its impact on the cathode behavior remains poorly understood. Here we show the correlation between capacity fading and phase/surface stability of an LiMn2O4 cathode. It is revealed that a combination of structural transformation and transition metal dissolution dominates the cathode capacity fading. LiMn2O4 exhibits irreversible phase transitions driven by manganese(III) disproportionation and Jahn-Teller distortion, which in conjunction with particle cracks results in serious manganese dissolution. Meanwhile, fast manganese dissolution in turn triggers irreversible structural evolution, and as such, forms a detrimental cycle constantly consuming active cathode components. Furthermore, lithium-rich LiMn2O4 with lithium/manganese disorder and surface reconstruction could effectively suppress the irreversible phase transition and manganese dissolution. These findings close the loop of understanding capacity fading mechanisms and allow for development of longer life batteries.

Understanding the breakdown mechanisms of polymer-based dielectrics is critical to achieving high-density energy storage. Here a comprehensive phase-field model is developed to investigate the electric, thermal, and mechanical effects in the breakdown process of polymer-based dielectrics. High-throughput simulations are performed for the P(VDF-HFP)-based nanocomposites filled with nanoparticles of different properties. Machine learning is conducted on the database from the high-throughput simulations to produce an analytical expression for the breakdown strength, which is verified by targeted experimental measurements and can be used to semiquantitatively predict the breakdown strength of the P(VDF-HFP)-based nanocomposites. The present work provides fundamental insights to the breakdown mechanisms of polymer nanocomposite dielectrics and establishes a powerful theoretical framework of materials design for optimizing their breakdown strength and thus maximizing their energy storage by screening suitable nanofillers. It can potentially be extended to optimize the performances of other types of materials such as thermoelectrics and solid electrolytes.

Crystallographic dislocation has been well-known to be one of the major causes responsible for the unfavorable carrier dynamics in conventional semiconductor devices. Halide perovskite has exhibited promising applications in optoelectronic devices. However, how dislocation impacts its carrier dynamics in the 'defects-tolerant' halide perovskite is largely unknown. Here, via a remote epitaxy approach using polar substrates coated with graphene, we synthesize epitaxial halide perovskite with controlled dislocation density. First-principle calculations and molecular-dynamics simulations reveal weak film-substrate interaction and low density dislocation mechanism in remote epitaxy, respectively. High-resolution transmission electron microscopy, high-resolution atomic force microscopy and Cs-corrected scanning transmission electron microscopy unveil the lattice/atomic and dislocation structure of the remote epitaxial film. The controlling of dislocation density enables the unveiling of the dislocation-carrier dynamic relation in halide perovskite. The study provides an avenue to develop free-standing halide perovskite film with low dislocation density and improved carried dynamics.

Chiral fermions in solid state feature

Intrinsically ferromagnetic 2D semiconductors are essential and highly sought for nanoscale spintronics, but they can only be obtained from ferromagnetic bulk crystals, while the possibility to create 2D intrinsic ferromagnets from bulk antiferromagnets remains unknown. Herein on the basis of ab initio calculations, we demonstrate this feasibility with the discovery of intrinsic ferromagnetism in an emerging class of single-layer 2D semiconductors CrOX (CrOCl and CrOBr monolayers), which show robust ferromagnetic ordering, large spin polarization, and high Curie temperature. These 2D crystals promise great dynamical and thermal stabilities as well as easy experimental fabrication from their bulk antiferromagnets. The Curie temperature of 2D CrOCl is 160 K, which exceeds the record (155 K) of the most-studied dilute magnetic GaMnAs materials, and could be further enhanced by appropriate strains. Our study offers an alternative promising way to create 2D intrinsic ferromagnets from their antiferromagnetic bulk counterparts and also renders 2D CrOX monolayers great platform for future spintronics.

In order to obtain a fundamental understanding of the interplay between charge, spin, orbital and lattice degrees of freedom in magnetic materials and to predict and control their physical properties(1-3), experimental techniques are required that are capable of accessing local magnetic information with atomic-scale spatial resolution. Here, we show that a combination of electron energy-loss magnetic chiral dichroism (4) and chromatic-aberration-corrected transmission electron microscopy, which reduces the focal spread of inelastically scattered electrons by orders of magnitude when compared with the use of spherical aberration correction alone, can achieve atomic-scale imaging of magnetic circular dichroism and provide element-selective orbital and spin magnetic moments atomic plane by atomic plane. This unique capability, which we demonstrate for Sr2FeMoO6, opens the door to local atomic-level studies of spin configurations in a multitude of materials that exhibit different types of magnetic coupling, thereby contributing to a detailed understanding of the physical origins of magnetic properties of materials at the highest spatial resolution.

We present a newly developed facility comprising a combinatorial laser molecular beam epitaxy system and an in situ scanning tunneling microscope (STM). This facility aims at accelerating the materials research in a highly efficient way by advanced high-throughput film synthesis techniques and subsequent fast characterization of surface morphology and electronic states. Compared with uniform films deposited by conventional methods, the so-called combinatorial thin films will be beneficial in determining the accurate phase diagrams of different materials due to the improved control of parameters such as chemical substitution and sample thickness resulting from a rotary-mask method. A specially designed STM working under low-temperature and ultrahigh vacuum conditions is optimized for the characterization of combinatorial thin films in an XY coarse motion range of 15 mm x 15 mm with submicrometer location precision. The overall configuration and some key aspects such as the sample holder design, scanner head, and sample/tip/target transfer mechanism are described in detail. The performance of the device is demonstrated by synthesizing high-quality superconducting FeSe thin films with gradient thickness and imaging surfaces of highly oriented pyrolytic graphite, Au (111), Bi2Sr2CaCu2O8+delta (BSCCO), and FeSe. In addition, we also have obtained clean noise spectra of tunneling junctions and the superconducting energy gap of BSCCO. The successful manufacturing of such a facility opens a new window for the next generation equipment designed for experimental materials research.

Rapidly discovering functional materials remains an open challenge because the traditional trial-and-error methods are usually inefficient especially when thousands of candidates are treated. Here, we develop a target-driven method to predict undiscovered hybrid organic-inorganic perovskites (HOIPs) for photovoltaics. This strategy, combining machine learning techniques and density functional theory calculations, aims to quickly screen the HOIPs based on bandgap and solve the problems of toxicity and poor environmental stability in HOIPs. Successfully, six orthorhombic lead-free HOIPs with proper bandgap for solar cells and room temperature thermal stability are screened out from 5158 unexplored HOIPs and two of them stand out with direct bandgaps in the visible region and excellent environmental stability. Essentially, a close structure-property relationship mapping the HOIPs bandgap is established. Our method can achieve high accuracy in a flash and be applicable to a broad class of functional material design.

SCM-14 (Sinopec Composite Material No. 14), a new stable germanosilicate zeolite with a 12x8x8-ring channel system, was synthesized using commercially available 4-pyrrolidinopyridine as organic structure-directing agents (OSDAs) in fluoride medium. The framework structure of SCM-14 was determined using rotation electron diffraction (RED), and refined against synchrotron X-ray powder diffraction (SXPD) data for both as-made and calcined materials. The framework structure of SCM-14 is closely related to that of three known zeolites: mordenite (MOR), GUS-1 (GON), and IM-16 (UOS). SCM-14 has the same projection as that of mordenite and GUS-1 when viewed along the 12-ring channels, and possesses two more straight 8-ring channels running perpendicular to the 12-ring channels. The structure of SCM-14 can be constructed by either the same layers as that of GUS-1 or the same columns as that of IM-16. Based on their structural relationship, three topologically reasonable hypothetical zeolites were predicted.

A new germanosilicate zeolite named SCM-15 (Sinopec Composite Material No. 15), the first zeolite containing a 3-dimensional (3D) channel system with interconnected 12-, 12-, and 10-ring channels (pore sizes: 6.1x7.2, 6.1x7.4, and 5.2x5.9 A), has been synthesized using neutral 4-pyrrolidinopyridine as organic structure-directing agents (OSDAs). Its structure has been determined by combining single-crystal electron diffraction (SCED) and synchrotron powder X-ray diffraction (SPXD) data. The unique open framework structure of SCM-15 is related to that of FOS-5 (BEC), ITQ-7 (ISV), PKU-16 (POS), ITQ-26 (IWS), ITQ-21, Beta polymorph B, and SU-78B, since all these framework structures can be constructed from similar chains which are connected through shared 4-ring or double 4-ring (d4r) units. Based on this relation, six topologically reasonable 3D large or extra-large pore hypothetical zeolites are predicted.

The "material genetic engineering" plan, based on the large data, is to investigate the high throughput design, fabrication and characterization techniques with the aim to shift the material research from traditional mode to high throughput mode with low cost and fast response speed, and to accelerate the research and development of new materials and achieve the goal of "double reduction halves". As the metal matrix composites (MMCs) exhibit multi-components and a thermodynamically non-equilibrium state during fabrication, some key issues occur and need to be addressed including: (1) for high throughput fabrication, currently developed high throughput technologies based on thermodynamically equilibrium conditions, such as spray printing and multi-node diffusion methods, are not applicable for MMCs; (2) for high throughput characterization, there is a lack of multi- dimensional, field and scale acquisition technique for the composition, morphology, microstructure and property of MMCs. In order to solve these problems, the progress on the research and development of high throughput fabrication and characterization techniques of MMCs was reviewed, especially, in the field of gradient reinforced MMCs and their high throughput combination characterization methods, which may promote the application of high throughput fabrication and characterization techniques in MMCs. Finally, the bottlenecks and prospects in the high throughput fabrication and characterization of MM Cs are proposed.

“材料基因工程”计划是以大数据作为支撑,采用高通量设计、制备和表征技术,促使材料研究从传统的试错模式转向低成本、快速响应的新模式,从而加快新材料的研发速度,实现研发成本和周期“双减半”的目标。金属基复合材料由于组分复杂、制备过程为热力学非平衡状态,带来一些新的问题需要解决,包括：(1) 高通量制备方法方面,针对合金块体样品开发的喷印合成法、多元结扩散法等基于热力学平衡理论的高通量制备技术无法直接用于金属基复合材料构件块体坯料的制造;(2) 高通量表征技术方面,缺乏针对金属基复合材料单一样品成分、形貌、组织、结构和性能的多维、多场、多尺度同步采集技术,以及针对阵列样品成分、形貌、组织与结构的快速表征技术。鉴于上述问题,本文综述了金属基复合材料高通量制备及表征技术发展现状及已取得的进展,特别是在增强体呈梯度分布的金属基复合材料制备技术与高通量组合表征方法上取得的突破,推动了高通量制备及表征技术在金属基复合材料领域的应用。最后指出了金属基复合材料高通量计算、制备方法和表征技术方面存在的瓶颈问题,并对高通量制备与表征技术的发展进行了展望。