Copper regulated facet dependent surface behavior promoting single crystal growth of sodium layered cathodes

In recent years, layered kagome magnets have emerged as promising platforms for Berry-curvature engineering and unconventional transport phenomena. Here, we present the single-crystal growth, magnetization, and electrical transport characterizations of the van der Waals-like layered antiferromagnet GdTi3Bi4. The system exhibits pronounced field-induced first-order phase transitions. Comprehensive frequency, temperature, and field-dependent ac susceptibility measurements, and Hall analysis, reveals the formation of a spin-cluster-like glassy magnetic phase attributed to noncollinear spin textures. Additionally, the system demonstrates a colossal anomalous Hall conductivity σ_xy^{A}~ 8.6(7)10^{3} Ohm-1 cm-1 at 2 K). Detailed scaling analyses reveal the coexistence of skew scattering and intrinsic Berry-curvature contributions to the anomalous Hall effect. First-principles calculations highlight flat-band near the Fermi level, with f-electrons of the Gd ion contributing large intrinsic Hall response. Thus, GdTi3Bi4 emerges as a rare layered kagome magnet, exhibiting Berry curvature-induced giant anomalous and spin texture-driven Hall responses, providing a versatile platform for exploring spin-texture physics and advancing low-dimensional spintronic functionalities.

Metal halide perovskites have recently begun to flourish in the field of optoelectronics. However, the inherent instability and grain boundary defects of traditional three-dimensional (3D) and two-dimensional (2D) polycrystalline films remain significant obstacles hindering their commercialization. Consequently, one-dimensional (1D) halide perovskite single crystals (PSCs) have garnered considerable attention due to their unique “molecular wire” structures. This distinctive structural constraint endows 1D PSCs with exceptional physical properties: strong quantum and dielectric confinement effects, broadband emission driven by self-trapped excitons, significant optoelectronic anisotropy, and excellent environmental stability. This article reviews the recent advances in 1D halide PSCs. We systematically explore the fundamental crystal structures and their derived photophysical properties, with a focus on elucidating the mechanisms behind their high quantum yields and nonlinear optical responses. Furthermore, various single-crystal growth strategies, ranging from slow cooling crystallization and inverse temperature crystallization to space-confined synthesis, are critically analyzed. Finally, we summarize the cutting-edge applications of 1D PSCs in high-performance UV–vis photodetectors, x-ray detectors, light-emitting diodes, and emerging polarization-sensitive devices.

From single-crystal growth to degradation suppression: The role of V2O5 doping in high-voltage spinel LiNi0.5Mn1.5O4

BaGa4Se7 is a promising infrared nonlinear optical (NLO) crystal, offering significant potential for mid-infrared applications. To further optimize its performance and explore new functional materials, we introduced Mg into the BaGa4Se7 lattice, successfully synthesizing a series of novel quaternary solid-solution NLO crystals. It confirms that the synthesized polycrystalline materials retain the same structure as the BaGa4Se7 crystal. Notably, Mg ions are incorporated into the crystal lattice by occupying two distinct cationic sites: the Ba2+ and Ga3+ sites. In the initial polycrystalline state, Mg preferentially occupies the Ba sites. During the subsequent slow, near-equilibrium single-crystal growth process, thermodynamic stability becomes the dominant factor governing Mg distribution. This leads to a redistribution of Mg ions: some Mg2+ ions that originally occupied the Ba sites are expelled toward the tail end of the growing crystal. In the main body of the crystal, a more stable and optimized occupancy pattern is established, where Mg2+ occupies both Ba and Ga sites in a specific equilibrium ratio. Remarkably, when this occupancy ratio reaches approximately 1:1, corresponding to the composition of Ba0.95Mg0.1Ga3.95Se7, the crystal demonstrates a significantly enhanced second-harmonic generation (SHG) response. Its SHG intensity at the fundamental wavelength of 1.064 μm is measured to be 1.86 times that of pure BaGa4Se7, while maintaining a high optical transmittance of up to 75% across the measured spectral range. This indicates a successful balance between enhancing the nonlinear optical coefficient and preserving excellent optical quality. However, as the Mg concentration is further increased, the substitution of Ga sites by Mg becomes dominant. This excessive substitution disrupts the optimal structural arrangement and charge balance, resulting in concurrent degradation of both nonlinear optical performance and overall optical properties. Our findings conclusively demonstrate that the nonlinear optical performance of BaGa4Se7 can be finely tuned and optimized through trace Mg substitution, highlighting the critical role of precise dopant control and site occupancy in developing next-generation high-performance infrared NLO materials.

Abstract We report the growth and physical characterization of high-quality single crystals of the layered manganese oxypnictide Ba 2 Mn 2 Bi 2 O, which features hexagonal Mn 2 Bi 2 O double layers separated by Ba 2+ ions. Magnetic susceptibility measurements reveal a broad hump around 170 K, characteristic of low-dimensional spin fluctuations, followed by two successive magnetic transitions at T N ≈ 32 K and T C ≈ 28 K. These transitions are confirmed by specific heat measurements, which show two distinct anomalies—unlike the isostructural compound Ba 2 Mn 2 Sb 2 O, which exhibits only one. Isothermal magnetization measurements demonstrate significant magnetic anisotropy, a clear hysteresis loop is observed for the field parallel to the c-axis below T C , providing direct evidence for the weak ferromagnetic component. The small magnetic entropy change (Δ S mag ≈ 0.43 J/mol·K) suggests significant short-range magnetic correlations above T N . Electrical resistivity follows a small-polaron hopping model with an activation energy of 0.04 eV, indicating semiconducting behavior. First-principles calculations including U -dependence checks reveal that Ba 2 Mn 2 Bi 2 O is a narrow-gap semiconductor (0.26 eV) with quasi-two-dimensional electronic structure, where carriers are confined within the Mn 2 Bi 2 O planes. The coexistence of antiferromagnetic order and weak ferromagnetism at low temperatures may arise from Dzyaloshinskii-Moriya interactions induced by strong spin-orbit coupling on Bi sites. This work establishes Ba 2 Mn 2 Bi 2 O as a promising platform for exploring correlated magnetism in heavy pnictide-based layered systems.

In this study, the growth of high-quality graphite single crystals from a molten metal flux at atmospheric pressure was optimized. The crystals were precipitated from a saturated iron–carbon solution by slowly cooling (4 °C/h) from a maximum temperature to reduce the carbon solubility. The graphite flakes were >25 square millimeters in area and >10 microns thick, with individual crystal grains as large as 1.2 mm2. The crystals were (0002) oriented, as determined by X-ray diffraction. The high structural quality of the graphite crystals was verified by Raman spectroscopy. For graphite with the natural distribution of carbon isotopes, the G-peak at 1580 cm−1 was narrow (~12 cm−1) and the defect peak (D-peak) was absent. To demonstrate the process versatility, graphite crystals enriched in the 13C isotope were grown at 5 degrees of enrichment. The Raman G-peak linearly shifted from 1580 cm−1 to 1520 cm−1 for graphite crystals enriched from 1 to 99% 13C. The etch pit densities from defect-sensitive etching ranged from 0 to 1.6 × 108 per cm2. The process was refined by examining the grain size and quality as functions of the carbon concentration in the starting sources, the carrier gas composition, and maximum temperature. The simplicity of this process suggests it can be scaled to produce very large graphite crystals that would be suitable for a wide range of technologies.

Applying a high magnetic field simulates microgravity conditions that suppress melt convection in germanium single crystal growth, thus reducing defect formations.

Although there have been several studies on the powder form, there has yet to be a report on the bulk crystal growth and its property studies of LiNiO2. In the present study, we report the first successful growth of a LiNiO2 single crystal by employing the optical floating-zone technique. Structural properties have been studied using single-crystal X-ray diffraction (XRD). The structural refinement of the single-crystal XRD data, along with the Laue diffraction patterns, confirms that this system crystallizes in a rhombohedral unit cell in space group R3m and the presence of a single grain along the length of the grown crystal. Furthermore, for the first time, we have observed and determined their superstructures as a function of temperature using single-crystal XRD. We have also conducted a study using the high flux of synchrotron X-rays to demonstrate the mechanism which drives the superstructure witnessed by the single-crystal XRD. Resonant elastic X-ray scattering was used to confirm the superstructure and the mixed valence state of different Ni sites. No additional ordering phenomena were observed, including magnetic or electronic ordering. Our study demonstrates the optimization of LiNiO2 growth parameters and provides information about atomic and electronic ordering in the system, including the onset of a superstructure phase. This will provide a basis for further work in developing improved cathode materials and understanding quantum spin liquids.

Abstract The CuBa 2 Ca 3 Cu 4 O 10+δ (Cu1234) superconductor exhibits a unique combination of high critical temperature (118K ambient T c ), high critical current density ( J c ), and high irreversibility field ( H irr ), i.e. the so-called triple-high attributes, making it a promising candidate for high-temperature and high-field applications. However, the growth of high quality single crystals has been hindered by contamination from traditional sample capsules used in conventional high-pressure synthesis, leading to suppressed T c . In this work, we develop a modified high-pressure sample assembly utilizing a capsule with MgO as the inner while Pt as the outer, which effectively prevents undesirable doping of Pt to Cu1234 that reduces T c . This approach enables the successful growth of Cu1234 single crystals with a sharp superconducting transition at T c ~115 K, comparable to the value of polycrystalline samples. Structural and compositional analyses confirm the phase purity, strong c -axis orientation, and a stoichiometry near the ideal Cu1234 formula. These high quality Cu1234 single crystals provide a reliable platform for elucidating the intrinsic mechanisms of the exceptional triple-high superconducting properties of the Cu1234 system.

Growth and investigation of mixed magnesium-zinc tungstate Zn Mg1-WO4 single crystals

The physical vapor transport (PVT) method is the most commonly applied growth technique for bulk SiC single crystals. Nowadays, the increasing demand of SiC substrates inevitably requires the adaption of PVT reactors to larger boule diameters. Since the boule quality and the single-crystal yield are primarily dependent on the thermal field inside the growth chamber and its stability, the control and optimization of the thermal conditions are the most crucial aspects to address. In this respect, the temperature difference along the seed, in the source and between source and seed, in addition to the growth temperature, are of particular interest. Due to the quasi-closed nature of the PVT system, in-situ measurements are hardly feasible, making numerical simulations the primary tool for analyzing the thermal field. But, since the high computational demand of these simulations restricts the number of cases that can be practically evaluated, numerical in-depth investigations are constrained. Attributed to this, the present study demonstrates an efficient way for constrained multi-objective optimization of the thermal field of PVT simulations by leveraging the correlation within the data through singular value decomposition (SVD). A 6-inch inductively heated PVT reactor is taken as a representative example and is optimized by combining machine learning models with numerical simulation data and optimization algorithms. In general, this approach enables the identification of optimal process parameters and reactor configurations, while revealing inherent tradeoffs between objectives and operational limitations, regardless of the PVT furnace operation principle (resistive or inductive) or seed crystal diameter (6-inch, 8-inch, etc.). Furthermore, it allows for an in-depth analysis of optimal settings, parameter sensitivities, interdependencies and solution robustness. • Machine learning model for thermal profile and thermal field prediction. • Machine learning model for growth rate prediction. • Constrained two- and three-objective optimization. • Evaluation of constrained multi-objective optimization results. • Sensitivity and uncertainty analysis.

In the production of monocrystalline silicon ingots with Czochralski (CZ) method, silicon seeds largely determine pulling success rate and the weight baring capacity of the dash necks. In this study, high-interstitial oxygen (HO) content silicon seeds were applied to CZ single-crystal growth to enhance mechanical robustness and suppress dislocation formation during 10-inch ingot production. Photoluminescence (PL), microscopic, and 3D X-Ray CT analyses revealed that HO seeds exhibited significantly fewer dislocations and microdefects after the seeding process compared to common seeds, confirming their superior resistance to thermal shock. 0.059° left shift in X-Ray Diffraction (XRD) pattern peak indicates oxygen can cause lattice expansion. Mechanical simulations and Vickers hardness indentation test indicated that interstitial oxygen increases lattice rigidity via a pinning effect, improving toughness (KIC increased 8.8%) despite reduced thermal conductivity (thermal stress increased 1.4%). Four-point bending tests further demonstrated that as interstitial oxygen concentration increased from 8 to 16 ppma, bending and shear strengths rose by 11.6% and 11.1%, respectively. During the necking process, oxygen content in HO seeds rapidly decreased from 17.56 ppma to 3.87 ppma within 10 mm, enabling earlier neck thinning without affecting the head oxygen level of the ingot. In industrial-scale experiments, 10-inch ingots grown from HO seeds achieved crystallization rates of 85–87%—roughly twice those obtained with common seeds—and a 4.3% average increase in output yield, which can bring over 80,000 USD benefit for 1 GW brick production. Furthermore, a 3800 mm-long, 10-inch ingot with a 6.72 mm neck was successfully grown using HO seeds, demonstrating their strong dislocation-suppression capability and potential for high-yield, large-scale stable CZ silicon production.

Scalable and sustainable synthesis methods for high-performance optoelectronic materials are essential to the advancement of next-generation optoelectronic and photonic technologies. Metal halide perovskites have rapidly gained prominence as versatile semiconductors across applications ranging from photovoltaics to lighting and sensing. However, their commercial deployment is hindered by the pervasive use of toxic lead-based compositions and the lack of environmentally friendly, industry-compatible fabrication processes. While lead-free alternatives based on group IVA elements such as tin have shown encouraging optoelectronic properties, their widespread adoption is limited by their chemical instability under ambient conditions. Antimony-based perovskite analogues are an emerging robust alternative, offering enhanced environmental stability, yet their synthesis has thus far depended on low-throughput single-crystal growth or solution processing routes that involve hazardous solvents and offer limited control over film structure and uniformity. Here, we demonstrate the first wafer-scale, room-temperature synthesis of high-quality lead-free Cs3Sb2Br9 and Cs3Sb2I9 thin films using radio frequency magnetron sputtering, a scalable, solvent-free deposition technique extensively employed in semiconductor and display manufacturing for the large-area deposition of metals, transparent conductive oxides and dielectric layers. The resulting films exhibit single-phase crystallinity, tuneable optical bandgap ranging from 2.17 to 2.71eV, and are well suited for UV-visible optoelectronics. Integrated into planar photodetectors, these materials achieve a photoresponsivity of 3.3A/W, a bandwidth of 11kHz, a linear dynamic range of 165dB, and a detectivity of 1.7 × 1015Jones, surpassing many state-of-the-art devices. These findings establish magnetron sputtering as a powerful platform for the scalable fabrication of lead-free perovskite optoelectronics and lay the foundation for their application beyondphotovoltaics.

CsPbBr3 single-crystal growth by temperature-lowering method as a case study for EGS4 benchmarking against commercial radiation detectors

The growth of high-quality organic single crystals is essential for probing intrinsic optoelectronic properties and molecular packing. However, the conventional vapor- and liquid-phase methods fail for structurally complex molecules like the non-fullerene acceptor (NFA) Y6, where thermal instability and steric hindrance from branched sidechains inhibit crystallization. Here, we report an additive-directed cocrystallization strategy to grow Y6-additive cocrystals (YACs) with controlled morphology and tunable thicknesses (18 nm to 341 nm). The single-crystal structure is determined by Micro Electron Diffraction Technology at first time. Growth mechanism studies reveal that additive molecules mitigate sidechain interference by enabling configuration coupling of π-π stacking, yielding YACs with central length of 450 μm and largest lengths of 1.5 mm. Generalizability is demonstrated across 10 kinds of Y6-like NFAs with axial/central symmetry and 2 kinds of effective additives. Most of YACs exhibit strong second harmonic generation (SHG) response. This work establishes a paradigm of single-crystal growth for structurally hindered complex molecules and provides a crystallographic basis for investigating the optoelectronic properties.

The growth of compositionally uniform InAs1-xSbx bulk crystals remains a formidable challenge due to severe solute segregation and morphological instability under terrestrial conditions. Here, we report the successful growth of a single-crystalline InAs0.933Sb0.067 alloy (x = 6.7 mol%) on an InAs seed via the vertical gradient freeze method aboard the China Space Station. Crucially, microgravity enables diffusion-dominated solidification by suppressing buoyancy-driven convection. As a direct consequence, the crystal is free of macroscopic voids and striations, exhibits a tenfold reduction in dislocation density, and maintains Sb compositional uniformity (±0.5 mol%) over its entire ~11 mm diameter and ~2.5 mm growth length. Moreover, the microgravity-grown crystal outperforms its terrestrial counterpart in both crystalline quality and electrical properties. These findings highlight that microgravity provides a unique pathway to overcome the intrinsic limitations of ground-based growth, enabling crystal quality unattainable on Earth - with potential relevance to advanced optoelectronic applications.

Growth, characterization and DFT studies of piperazinium dihydrogen phosphate single crystal: investigations on optoelectronic and antibacterial activities

Reduced graphene oxide (rGO) has attracted interest as a potential, cost-effective alternative to graphene layers produced by single-crystal thin-film growth techniques. Its solubility in various solvents, the ability to tune its optical and electrical properties, the ability to manipulate the optoelectronic properties of rGO-based heterojunctions, and the possibility of depositing it on flexible substrates broaden its potential applications, from electro-optical communications to environmental monitoring. In this work, we present a characterization of reduced graphene oxide (rGO) deposited on p-type Si3N4/Si substrate using different techniques such as Raman spectroscopy, optical transmittance, and current-voltage measurements under dark and illuminated conditions in the 400-700 nm range. Furthermore, the temperature dependence of the photocurrent of the rGO-based photoconductive device was studied in the temperature range from 300 K to 77 K. It has been shown that the electron transport mechanism through the p-type rGO/SiN/Si heterojunction at low voltage involves mainly a hopping process at 77 K and a thermionic mechanism at room temperature. Furthermore, the Fowler-Nordheim tunneling and trap-limiting mechanisms allow the presence of charge carriers in the device at both temperatures. Estimation of the main figures of merit, responsivity, detectivity, and NEP, shows an improvement in photodetection performance at low temperatures.

Cimetidine, a popular histamine H2-receptor antagonist, represents a complex structural landscape exhibiting multiple forms. Attempts to synthesize a bicomponent salt with fumaric acid suffered from crystallization challenges in the past, especially toward the growth of anhydrous single crystals. In this work, we address these crystallization challenges by adopting an alternative crystallization approach involving ionic liquids and analyzing the structural landscape with a large synthon-based approach. Two novel forms of cimetidine fumarate were isolated. The structural differences in the forms of cimetidine fumarate were further explored by using different coformers as structural probes.