This study investigates the HTHP treatment of single-crystal CVD diamonds synthesized via microwave plasma CVD (MPCVD). Under 5.5 GPa and varying temperatures, the single-crystal diamond achieves a controllable color transition from initial brown to pink and finally to colorless transparency. We clarify that the pink color originates from the formation of abundant nitrogen-vacancy (NV) centers: high temperatures destabilize vacancy clusters (the root cause of brown color) in as-grown diamonds, releasing vacancies that bind with lattice nitrogen atoms to form NV centers. This process boosts the photon count signal of NV centers by -8-fold while retaining the coherence time. Simultaneously, HTHP treatment improves the fracture toughness by 2.2-fold, realizing synchronous enhancement of quantum and mechanical properties. Collectively, this work provides new insights into the evolution of defect structures in CVD diamonds and establishes a novel technical route for fabricating high-performance quantum diamonds applicable to quantum sensing and gemstone fields.

Graphite intercalation compounds (GICs) serve as a highly tunable platform for exploring phonon-mediated superconductivity in lightweight materials. While theoretical models have long predicted that densely packed, first-stage (stage-1) sodium-intercalated graphite (Na-GIC) could host elevated critical temperatures (Tc), its experimental synthesis has remained a formidable challenge. Here, we report the realization of stage-1 Na-GIC that exhibits bulk superconductivity and achieves a maximum onset Tc of ∼31 K, setting a record for all known GIC systems. By employing a room-temperature mechanical synthesis with an excess sodium reservoir, followed by lattice compression, we force a sequential staging transition in Na-GIC─from an initial stage-8, through an intermediate stage-2, and ultimately to the densely intercalated stage-1 phase at 15.6 GPa. By correlating room-temperature in situ synchrotron X-ray diffraction with evolutionary structural searches, we identify the host of this high-Tc state as an orthorhombic NaC3 structure with Imma symmetry. First-principles calculations reveal a remarkably strong electron-phonon coupling (λ ∼ 2.0), dominated by interactions between out-of-plane carbon π electrons and low-frequency Na/C vibrations. Our findings not only capture the elusive stage-1 Na-GIC but also establish pressure-driven compositional tuning as a robust strategy to unlock high-Tc states in carbon-based superlattices.

LaCrSb3 is a material exhibiting both quasi-two-dimensional spin fluctuations and three-dimensional magnetic interaction characteristics. By measuring the isothermal magnetization of single-crystals and conducting a systematic critical behavior analysis, we clarify the critical properties of its ferromagnetic phase transition and the intrinsic magnetic interaction mechanism. Based on high-precision isothermal magnetization data measured in the vicinity of the critical point, the Curie temperature for the ferromagnetic-paramagnetic phase transition is determined to be T-C = 126 K, with the critical exponents obtained as beta = 0.376, gamma = 1.417 and delta = 4.76 via the self-consistent iterative method based on the Arrott-Noakes equation. The reliability of these critical exponents is verified by the Widom scaling law, the magnetic state scaling equation and other analyses. A comparison with theoretical models demonstrates that the critical behavior of the magnetic phase transition in this system basically belongs to the universality class of the three-dimensional Heisenberg model. This conclusion is further confirmed by the distance-dependent decay behavior of the exchange interaction J(r), revealing the dominant role of isotropic direct exchange interactions in this system. Finally, drawing on research findings of other quasi-two-dimensional magnetic materials, this work proposes that LaCrSb(3 )may exhibit nonzero temperature magnetic order in the two-dimensional limit, thereby possessing important theoretical research significance and promising practical application prospects.

Large-volume presses (LVPs) are widely utilized in diverse research fields—including high-pressure physics, chemistry, materials science, and Earth and planetary sciences—to investigate the physical and chemical properties of materials under extreme high-pressure and high-temperature conditions. A prerequisite for achieving reproducible property measurements is the determination and control of pressure within experimental setups. However, the lack of precise pressure calibration in LVPs hinders the broader application of such devices in ultrahigh-pressure studies. This study employs a suite of standard phase transition-based pressure markers—comprising metallic conductors, semiconductors, and minerals—through both in situ and ex situ identification approaches, to establish pressure calibration curves ranging from 0.4 to >30 GPa for various types of LVP installed at the Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing, including piston–cylinder, cubic, and multi-anvil presses. The results provide a unified and traceable pressure reference for high-pressure experiments conducted at HPSTAR, while also offering technical guidance and calibration standards for other researchers utilizing similar LVP systems, thereby enabling more consistent comparison between different laboratories. This work facilitates the advancement of LVP research toward broader applications in higher-pressure regimes.

We have investigated the magnetic properties of LaCrSb3 by analyzing DC magnetic susceptibility and isothermal magnetization within the frameworks of Takahashi and Kuz'min's theory. The Curie temperature, effective and spontaneous moment agrees well with previous reports. The location of LaCrSb3 in Deguchi-root Takahashi plot is found on the e = 0.05 line (where e =m/m ' is a parameterized ratio of in-plane (m) and out-of-plane (m ') effective mass), indicating a two-dimensional nature. The shape parameter s is estimated to be 0.706(7), implying competing magnetic interactions in this system. We also discuss the potential of LaCrSb3 as a 2D spintronic material.

Selective laser melting (SLM) provides a route to produce high-strength pure titanium, but the ductility of as-fabricated material is often limited by printing-induced pores, lack-of-fusion defects and heterogeneous solidification microstructures. In this study, high-pressure high-temperature (HPHT) treatment was investigated as a pressure-assisted post-processing strategy to tailor pore characteristics, defect structures and tensile properties in SLM pure Ti. Among the processing conditions examined, treatment at 5 GPa and 500 °C for 5 min produced the best strength–ductility balance. The detectable porosity decreased from 2.83% to 0.08%, while the yield strength increased from approximately 700 to 1000 MPa and the elongation improved from approximately 1% to 19%. X-ray diffraction confirmed that the matrix remained dominated by hcp α-Ti, with no detectable β-Ti, ω-Ti or secondary precipitates within the detection limit of laboratory XRD. The improved mechanical response was mainly associated with coupled defect elimination and defect-structure regulation. GPa-level pressure promoted pore closure and suppressed defect-driven premature fracture. Meanwhile, dense dislocation substructures and 10–50 nm deformation twins provided additional barriers to dislocation motion and promoted local strain accommodation. These results demonstrate HPHT treatment as an effective non-alloying post-processing route for optimizing the strength–ductility balance of additively manufactured pure titanium through coupled defect elimination and defect-structure regulation.

Strain engineering under extreme non-hydrostatic compression provides a unique pathway to tune material properties, yet the evolution of fine structural parameters under such conditions remains unexplored. Here, we systematically investigate the elastic-plastic deformation behaviors of nickel and ceria (CeO2) across varying grain sizes (8-200 nm) under non-hydrostatic compression up to similar to 35 GPa using synchrotron-based radial X-ray diffraction in a diamond anvil cell. We find that the differential lattice aspect ratio in nickel plateaus at a relatively low pressure due to yielding, whereas ceria exhibits continuous elastic deformation with an increasing aspect ratio within the tested pressure range. Furthermore, as the grain size decreases to similar to 8 nm, the maximum differential lattice aspect ratios of {200} plane in both nickel and ceria reach similar to 3.2%. The lattice strain anisotropy experiences a multifold enhancement in nickel as the grain size reduces from similar to 200 nm to similar to 8 nm due to the suppression of dislocation slip. In contrast, this increase of anisotropy by reduction of grain size attenuates in ceria, a phenomenon attributed to the activation of nanoscale plasticity in nanoceramics. These size-dependent deformation mechanisms are further corroborated by microstructural evidence from transmission electron microscopy. Our results highlight the broad tunable parameter space in both metallic-and covalent-bonded nanomaterials via non-hydrostatic high-pressure strain engineering, and would help to understand the highpressure strengthening effect in nanograined metals.

Metals usually fracture catastrophically at cryogenic temperatures and soften rapidly at high temperatures. This dilemma arises from the incompatibility of strengthening mechanisms across vast temperature regimes. Here, this work unveils a self-adaptive dislocation morphing mechanism in a model NbTaTi-based refractory high-entropy alloy (RHEA) that enables exceptional strength and ductility from 4 K to 1673 K. At cryogenic temperatures, dislocation kinking coupled with deformation twinning suppresses the ductile-to-brittle transition. At ambient conditions, the sequential activation of edge and screw dislocations sustains work hardening. At elevated temperatures, enhanced dislocation interactions generate jogs, multijunctions, and helical dislocations, promoting superplasticity up to 250%. This intrinsic, temperature-responsive evolution of dislocation modes offers a defect engineering strategy for designing RHEAs capable of enduring extreme environments.

Finding electrocatalysts with both ultra-low overpotential onsets and Tafel slopes is the ultimate goal for largely reducing the electricity input for generating green hydrogen energy. Here, we report the finding of a high-performance oxygen evolution reaction (OER) catalyst (FeCoNi)B among several medium/high-entropy metal borides, which is superior to hundreds of OER catalysts studied so far. Our density functional theory calculations of the surface d-band centers of the boride catalysts revealed a "volcano"-type plot with (FeCoNi)B located at the summit, confirming its excellent OER performance. The presence of different d-band centers in the multi-cations supports our idea of spontaneous adoption of a shifting catalyzing center by the catalyst for maximizing its OER activity. This is validated by adsorption energy calculations on a hydroxylated surface. The OER rate-determining step was determined to be the second elementary reaction, suggesting subsequent preferential desorption of oxygen-containing intermediates from cations with relatively low d-band centers. This work pioneers a novel concept of shifting catalytic centers in medium-/high-entropy catalysts and demonstrates a promising method to achieve significant catalytic performance through d-band center modulation.

Two-dimensional (2D) diamond has aroused remarkable interest in nanoelectronics and optoelectronics, owing to its superior properties and flexible characteristics compared to bulk diamond. Despite significant efforts, great challenges lie in the experimental synthesis and transformation conditions of 2D diamond. Herein, we have demonstrated the experimental preparation of high quality 2D diamond with controlled thickness and distinguished properties, realized by laser-heating few-layer graphene in a diamond anvil cell. The quenched 2D diamond exhibited a narrow T2g Raman peak (linewidth ~3.6 cm-1) and intense photoluminescence of SiV- (linewidth ~6.1 nm) and NV0 centers. In terms of transformation mechanism, atomic structures of hybrid phase interfaces suggested that the intermediate rhombohedral phase subtly mediate hexagonal graphite to cubic diamond transition. Furthermore, the tunable optical bandgap and thermal stability of 2D diamond sensitively depend on its sp3 concentration. We believe our results can shed light on the structural design and preparation of many carbon allotropes and further uncover the underlying transition mechanism.

Self-intercalation in transition metal dichalcogenides (TMDs) offers a unique strategy for doping and spin ordering that preserves structural integrity, minimizing lattice distortions. This modification introduces additional electron density, spin states, and potentially spontaneous superlattice formation. Combining with further high-pressure modulation, more quantum phenomena could be induced for new physics exploration. Here, we present a high-pressure study of the self-intercalated compound V_{1/4}VS_{2}, where antiferromagnetic order arises from 3d electrons localized on the vanadium atoms intercalated between the layers. Under pressure, these localized electrons progressively delocalize, leading to the suppression of the antiferromagnetic order and the emergence of non-Fermi liquid behavior near 9 GPa, signaling an antiferromagnetic quantum critical point. Under higher pressure, a Lifshitz transition-induced superconductivity is observed, while the crystalline symmetry remains preserved up to 104.4 GPa. Notably, this marks the first observation of superconductivity in a self-intercalated TMD under pressure. These findings highlight V_{1/4}VS_{2} as a model two-dimensional system for exploring pressure-induced quantum criticality, electronic topological transitions, and related nontrivial superconductivity, paving the way to new physics by fully exploring the potential of self-intercalated TMDs.

Mineral resources on Earth are finite, but wood is renewable. Therefore, replacing limited industrial materials with modified wood remains a long-term pursuit. This study processed samples of three wood types, including balsa (Ochroma lagopus), basswood (Tilia tuan), and African blackwood (Dalbergia melanoxylon), with a large volume cubic press to compress these samples at room temperature under high pressure. The effects of high-pressure treatment on the air dry density, compressive strength, and elastic modulus of the three wood species were analyzed, and changes in their internal microstructures were observed using CT and scanning electron microscope. The results showed that the physical and mechanical properties of all three wood species improved. After high-pressure processing at 5.50 GPa, the density of balsa, basswood, and African blackwood increased by 239%, 112%, and 11%, respectively. Additionally, the surface hardness increased by 79%, 46%, and 15%, respectively, and the compressive strength increased by 33%, 9%, and 28%, respectively. Notably, the specific strength of compressed African blackwood (101.55 kJ/kg) approaches that of aluminum alloys (109.23 kJ/kg). The results demonstrate that African blackwood is lighter than ceramic materials. Furthermore, this wood offers superior electrical insulation and thermal insulation compared to aluminum alloy. Crucially, African blackwood possesses high specific strength, and this property gives it significant potential to replace aluminum alloy in numerous special environments. Such application supports sustainable development for future industries. In conclusion, this research opens new possibilities for high-value wood applications.

As an A-site-vacant perovskite-type oxide, ReO3 undergoes sequential pressure-driven structural phase transitions associated with rotations of ReO6 octahedra. In this work, we report the discovery of a superconducting T c(P) dome for the rhombohedral-I phase of ReO3 in the pressure range 12-39 GPa. The rhombohedral-I phase is featured by the nearly close-packed oxygen layers intercalated with Re cations, which is reminiscent of superhydride superconductors. The observed maximum T c (∼ 17.8 K) sets the record of high T c among 5d transition-metal-oxides. First-principles calculations reveal that the strong hybridizations between Re-5d and O-2p orbitals significantly enhance the density of states at the Fermi level and the close-packed oxygen framework directly enhances the electron-phonon coupling. We attributed the observed record high-T c to the synergistic effect of strong hybridizations and oxygen sublattice contribution. The present work establishes a rare case that the light-element oxygen lattice plays a crucial role in assisting the emergence of high-T c superconductivity and provides more clues for further exploring new superconductors in 5d transition-metal oxides via high-pressure or heterostructure engineering.

The rare-earth orthoferrite family is prototypical strongly correlated systems, known for its highly tunable ferromagnetism properties. Among these materials, Sm0.5Y0.5FeO3 exhibits potential for applications becaue of its near room temperature spin reorientation transition. However, a comprehensive understanding of the spin reorientation and structural phase transitions in Sm0.5Y0.5FeO3 under pressure remains unclear. In this work, we present spectral (Raman and synchrotron x-ray diffraction) and electrical (electrochemical impedance spectroscopy) evidence of spin reorientation and an isostructural phase transition in Sm0.5Y0.5FeO3 up to 50 GPa. DFT calculations demonstrate that. while Sm0.5Y0.5FeO3 retains its semiconducting behavior under pressure, it undergoes a pressure-induced spin reorientation transition, with the magnetic easy axis switching from the (100) to the (001) direction. These findings establish pressure as a critical parameter for tuning correlated-electron behavior in Sm0.5Y0.5FeO3, paving the way for applications in spintronic and next-generation quantum transportation devices.

CrSb, as a prototypical candidate compound of altermagnetism, has attracted significant attention due to its unique magnetic properties. In this study, we combine systematic electrical transport measurements with first-principles calculations to investigate the possible realization mechanisms of topological semimetal states in CrSb and their manifestations in quantum transport phenomena. Our high-field magneto-transport measurements reveal that the magnetoresistance of CrSb exhibits no sign of saturation up to 35 T, following a distinct power-law dependence with an exponent of 1.48. The nonlinear Hall resistivity curve further indicates a multiband charge transport mechanism. Under high magnetic fields, we observe pronounced Shubnikov-de Haas (SdH) quantum oscillations and discernible Zeeman-effect-induced band splitting at 1.6 K. Systematic Fermi surface and band calculations combined with Berry phase analysis confirm the nontrivial topological character of this material (with a Berry phase approaching π). These findings not only provide crucial experimental evidence for understanding the electronic structure of CrSb, but also establish an important foundation for investigating topological quantum states in altermagnets.

The search for novel nitride superconductors with superior mechanical properties is highly demanded for many potential applications, which, however, have been scarcely succeeded for the late 5d transition-metal nitrides, especially for the binary W-N compounds. Here we report the experimental identification of superconductivity in cubic cP6-WN with the NbO-type structure by electrical transport, magnetization, and specific heat measurements, based on high-pressure synthesized samples. The superconducting properties of cP6-WN are well determined and it belongs to a bulk type-II superconductor with a critical onset temperature of Tc = 2.86 K, showing weak electron-phonon coupling, short coherence length, and high upper critical field, likely due to its unique electronic and structural features. Pressure may slightly enhance electron-phonon interactions for gently promoting its Tc up to 3.83 K at 81 GPa, indicating the remarkable robustness of its superconductivity to external stress. This, combined with its exceptional mechanical hardness that rivals that of tungsten carbide (WC), makes it a compelling candidate for fabrication of durable superconducting electronics and coatings operating under high-stress conditions.

The emergence of extremely large magnetoresistance in kagome compounds is rare yet highly intriguing, despite its presence in various other material systems. In this study, we report a comprehensive investigation of the specific heat, magnetotransport properties, electronic structure, and de Haas-van Alphen effect in the kagome compound Ni3In2Se2. This compound exhibits an impressive magnetoresistance of 8600% at 2 K and 9 T, along with a high carrier mobility of approximately 9000 cm2/V s. Hall measurements reveal an anomalous behavior at low temperatures, which is likely attributed to the multi-carrier effect. Density functional theory calculations suggest that the large anisotropic magnetoresistance in Ni3In2Se2 is primarily due to the geometry of its Fermi surfaces, which is further characterized by de Haas-van Alphen effect measurements. These results highlight Ni3In2Se2 as a promising platform for electronics and spintronics applications in kagome compounds.

As a prototypical altermagnet, RuO2 has been subject to many controversial reports regarding its magnetic ground state and the existence of the crystal Hall effect. We obtained a high-quality RuO2 single crystal with a residual resistivity ratio (RRR = 152), and carefully measured its magnetization, longitudinal resistivity (ρxx) and Hall resistivity (ρyx) in magnetic field up to 35 T. We also calculated its electronic bands and Fermi surface, and conducted numerical simulations for its transport properties. It was found that no magnetic transition occurs below 400 K, and that all the transport properties are consistent with the numerical simulation results, indicating that the magneto-transport properties originate from the intrinsic electronic structure and are dominated by the Lorentz force. Particularly, no crystal Hall effects were observed in our RuO2 samples and both magnetoresistance and Hall resistivity follow a scaling behavior. Additionally, by comparing theoretical calculations with experimental data, we found that the magneto-transport properties calculated using the altermagnetic structure are not consistent with the experimental observations, whereas those calculated based on the non-magnetic structure show excellent agreement. These results demonstrate that RuO2 is a typical semimetal, rather than an altermagnet. The altermagnet candidate RuO2 has sparked recent debate in the scientific community regarding its magnetic ground state and the existence of a crystal Hall effect. Here, the authors synthesize high-quality RuO2 crystals and provide comprehensive measurements to reveal that its magneto-transport properties obey scaling law and align with a non-magnetic semimetal model, challenging the notion of RuO2 as an altermagnet and refining our understanding of its electronic structure.