We have performed in situ time-resolved x-ray diffraction at 100 GPa on laser-shocked CaSiO3 glass to investigate the glass-to-crystal transition. At this extreme pressure, we observe the ultrafast crystallization of the CaSiO3 perovskite structure from the compressed amorphous phase, with a typical nucleation time of 1.69 f 0.10 ns and a final grain size of 20 nm. The grain size temporal evolution suggests a diffusion-controlled transformation. Moreover, the observed concomitant explosive grain growth together with the release wave arrival into shocked CaSiO3 also suggests a role of the release in the nucleation process.

Revealing the local atomic structure of doped halide perovskite quantum dots (QDs) is crucial for understanding how metal-ion incorporation tunes their optoelectronic properties. In particular, dopant-lattice interactions in CsPbI3 are governed by short-range distortions and dynamic lattice fluctuations that cannot be resolved by conventional diffraction methods. Here, we present a systematic investigation of Zn-doped CsPbI3 QDs over a wide Zn : Pb ratio (0-1.5) by combining optical spectroscopy with extended X-ray absorption fine structure (EXAFS) and X-ray total scattering analyses. An optimal Pb : Zn ratio of 1 : 1.25 yields a markedly enhanced photoluminescence quantum yield of up to 97%, accompanied by shortened carrier lifetimes, whereas excessive Zn doping deteriorates the optical performance. EXAFS reveals shortened Pb-I bond lengths, a general increase in coordination numbers, and reduced local octahedral distortion in Zn-doped samples compared with pristine CsPbI3 QDs. Complementary pair distribution function (PDF) analysis demonstrates PbI6 octahedral tilting and decreased atomic displacement parameters, indicating stabilisation of lattice fluctuations. These structural modifications collectively weaken electron-phonon coupling and suppress non-radiative recombination pathways, thereby accounting for the enhanced emission efficiency. This work establishes a direct correlation between dopant-induced local structural stabilisation and optoelectronic performance in CsPbI3 QDs.

We report thermodynamic properties, including equation of state, principal Hugoniot, heat capacity, and Grüneisen parameter, for beryllium under density–temperature conditions of ρ = 3.0–9.0 g/cm3 and T = 5–10 000 eV, using an extended first-principles molecular dynamics method together with finite-temperature exchange–correlation functionals. Compared with zero-temperature exchange–correlation models, our results exhibit appreciable differences of about 3% in modeling the equation of state. Thermal excitations of K-shell electrons, delocalization of wave functions, and the merging of energy bands for beryllium along the Hugoniot curve are also presented. In addition to the application of these thermodynamic data to inertial confinement fusion and high-energy-density physics, our results may also serve as useful benchmarks for investigating thermal exchange–correlation effects on thermodynamic properties of warm dense matter, and further help to elucidate the mechanisms of inner-shell electron excitation.

Graphitic carbon nitride (g-C3N4) is a promising photocatalyst for environmental remediation and energy conversion. In this work, we systematically explored the effects of high pressure and high temperature (HPHT) treatments on the structural and photocatalytic properties of g-C3N4. The material was sintered in a large cavity piston-cylinder press at 600 degrees C under pressures up to 3 GPa, and its photocatalytic activity was evaluated via Rhodamine B (RhB) degradation. Synchrotron X-ray total scattering and pair distribution function (PDF) analysis were employed to probe local structural changes, while X-ray photoelectron spectroscopy (XPS) was used to monitor the N2C/N3C ratio and the formation of carbon vacancies. High-pressure treatment alone led to reduced carbon content, increased N2C/N3C ratios, the generation of vacancy defects, and enhanced photocatalytic efficiency. At constant pressure, increasing temperature further promoted nitrogen loss and defect formation. X-ray total scattering and pair distribution function (PDF) analysis showed that pressure introduced mild long-range disorder, which was largely reversible upon heating. However, combined HPHT treatment induced broader PDF peaks and disrupted interlayer correlations, indicating enhanced stacking disorder. These results demonstrate that controlled HPHT processing enables precise tuning of the atomic structure and photocatalytic performance of g-C3N4, offering a strategy for advanced photocatalyst design.

The Hugoniot equation of state, elastoplastic transition, and spall behavior of the Fe–36Ni Invar alloy were systematically investigated over a pressure range of 3–33 GPa. The Hugoniot elastic limit was determined to be between 0.8 and 1.0 GPa. Within the investigated pressure range, the shock velocity (Us)–particle velocity (Up) relation is linear, expressed as Us=3.703+1.888Up. The spall strength of Invar, determined using the acoustic method, is found to increase with shock stress, ranging from 2.5 to 3.7 GPa.

Abstract Davemaoite (CaSiO 3 perovskite) is the third most abundant mineral in Earth's lower mantle and a major constituent of both pyrolitic and basaltic mantle compositions. Despite its geophysical importance, its physical properties at lower‐mantle conditions remain poorly constrained because micrometer‐sized davemaoite cannot be recovered to ambient conditions. Here, we present shock‐wave experimental measurements of the Hugoniot equation of state, longitudinal sound velocity, and shock temperature of CaSiO 3 glass to pressures relevant to the lowermost mantle. CaSiO 3 glass transforms into davemaoite above ∼80 GPa under shock compression. Direct measurements of the longitudinal sound velocity of davemaoite show that it is significantly slower than the other major lower‐mantle phases, providing the first experimental constraints on its elastic properties near core‐mantle boundary conditions. The longitudinal sound velocity and shock‐temperature measurements further indicate melting of davemaoite above ∼4,500 K at ∼110 GPa. This measured melting temperature is substantially lower than those predicted by theoretical studies. The results provide new constraints on the physical properties of davemaoite and have important implications for interpreting deep‐mantle heterogeneity, including large low‐shear‐velocity provinces, as well as for understanding the crystallization and evolution of Earth's early magma ocean.

Tungsten is an elemental metal known for its high melting point and hardness, but experimental information about its mechanical properties at high pressures is limited. Here, longitudinal sound velocity, V-L, of tungsten compressed in a diamond anvil cell up to P = 141 GPa was measured using picosecond laser ultrasonics. Thus, the range of static pressures for which its V-L is known was extended by more than one order of magnitude, corresponding to a 31% increase in density compared with that at atmospheric pressure. We have found that the V-L grows monotonically with pressure and reaches 7.75 +/- 0.18 km/s at P = 141 GPa. Applying an earlier published equation of state, rho(P), we derived the pressure-dependent shear modulus, G(P), and transversal sound velocity, V-T(P), of tungsten. Both parameters continuously increase with pressure, but their growth rates diminish upon compression. Based on these data, the evolution of tungsten ductility/brittleness with pressure was assessed using Pugh's ratio, B/G, and a transition from intermediate- to weakly-brittle state was recognized. Combining our G(P) with previously measured yield strength of tungsten at high pressures, sigma(y)(P), the ratio partial derivative sigma(y)/partial derivative G = 0.017 +/- 0.002 was established, and sigma(y) similar to 7.5 GPa at P = 141 GPa was estimated from linear extrapolation. Finally, we have found that the linear dependence of V-L on density, known as Birch's law, holds for tungsten up to the maximal pressure of our work.

Understanding of the observed seismic velocities requires knowledge of the sound velocities of constituent minerals in Earth's interior. As the third most abundant phase of the lower mantle, calcium silicate perovskite (davemaoite) has a significant influence on mineralogical models. Experimental measurements of sound velocities of davemaoite at lower mantle conditions are scarce due to its unquenchable nature. Here, we synthesized quenchable Ti-bearing calcium perovskite as a good analogue for unquenchable davemaoite and investigated its crystal structure, equation of state, refractive index, and sound velocity under high pressure. Tetragonal Ti-bearing calcium perovskite is stable without phase transition up to similar to 48 GPa but exhibits enhancing octahedral rotation and distortion with increasing pressure. The refractive index of Ti-bearing calcium perovskite increases slightly with pressure ranging from similar to 1.93 at 15 GPa to similar to 2.04 at 73 GPa and was used to calculate longitudinal sound velocity by time-domain Brillouin scattering measurements. Applying density, isothermal bulk modulus and its pressure derivative obtained by the constructed equation of state, then transverse sound velocity of Ti-bearing calcium perovskite was derived. Sound velocities of Ti-bearing calcium perovskite are significantly lower than those of CaSiO3, especially transverse sound velocity. Low sound velocities of calcium perovskite contribute to the low sound velocities of subducted basalt and may provide an alternative interpretation for the low seismic velocity signatures in the lower mantle.

Semiconductor SnS with excellent physical properties has attracted wide attention due to its nontoxicity and abundance in the earth. SnS crystallizes in an orthorhombic structure (Pnma) at ambient conditions. Its unit cell comprises double layers stacked with weak van der Waals-like coupling, rendering it sensitive to high temperature (T) and high pressure (P) conditions. Here we experimentally demonstrate that SnS undergoes two phase transitions under high pressure by in situ x-ray diffraction and Raman spectroscopy. The Pnma SnS transforms into the Cmcm phase above 22.4 GPa, and a CsCl-type structure (Pm3m) emerges at around 43.2 GPa, coexisting with the Cmcm phase up to about 66 GPa. SnS completely transforms into the Pm3m phase by 67.9 GPa. Theoretical calculations are performed to elucidate the structural characteristics of the high pressure Cmcm phase. Optical absorption and electrical transport experiments confirm that high pressure can reduce the band gap of SnS, leading to metallization. Additionally, the P-T phase diagram of SnS has been investigated by in situ Raman spectroscopy. The Pnma to Cmcm phase transition boundary of SnS at high P-T conditions is depicted experimentally. The effects of high temperature and high pressure on crystal structure, and optical and electrical properties of SnS are reversible upon returning to ambient conditions. Our research offers insights into the structures and physical properties of the group IV-VI monochalcogenides under extreme conditions and their potential applications in electronics and optoelectronics.

High-pressure elastic and plastic behavior of the amorphous solid, formed after solidification of the mixture of methanol and ethanol in the volume ratio 4:1 (4:1-ME), was investigated using the technique of time-domain Brillouin scattering (TDBS). Isotropic nature of this solid, whose bulk modulus exceeds that of diamond at pressures above 60-70 GPa (provided the earlier-measured dependence of its density on pressure, rho(P), holds at P>60 GPa), was confirmed thanks to the high 3D resolution of the TDBS technique. This permitted establishing of the relationship between elastic and plastic properties at high pressures because elastic response of the amorphous solid was not affected by anisotropy and texture, as is the case for crystalline solids. Using the TDBS technique, we measured pressure dependence of the Brillouin-oscillation frequencies, f(B)(P), of 4:1-ME and, consequently, of its longitudinal sound velocity, V-L(P), and shear modulus, G(P), to P = 78 GPa. To access pressure dependence of its yield strength, sigma(y)(P), we used the here-established secondary pressure scale, based on our experimental f(B)(P), and measured the maximal pressure gradients in the compressed samples which are proportional to sigma(y). We found that the rapid increase of bulk modulus of 4:1-ME with pressure, deduced from the rho(P) measured earlier to 60 GPa and extrapolated here to 78 GPa, is not accompanied by a similarly strong increase of its shear modulus and yield strength. The two parameters remain significantly below those of diamond at atmospheric and high pressures. Comparison of the here-measured sigma(y)(P) with the dependences B(P) and G(P) indicated that sigma(y) can be similarly well approximated by linear functions where B or G serves as the variable.

Hugoniot data for nickel (Ni) were extended to 305 GPa through plate-impact experiments using a two-stage light gas gun. Combining our results with previously published data, we determined the shock velocity (Us)- particle velocity (Up) Hugoniot relation for Ni to be: Us = 4.653(62) + 1.420(23)Up. The thermodynamic parameters of Ni were derived through a joint analysis of the Hugoniot and static compression data, allowing us to extend the equation of state (EOS) to conditions relevant to Earth's inner core. Additionally, we reanalyzed the EOS of iron based on a recently published static compression data. Our study suggests that the density of pure iron is 0.59 (20) g/cm3 higher than that of the inner core. Moreover, adding 10 wt% Ni to iron increases this density deficit by approximately 0.10 g/cm3.

The group V-VI semiconductor material getchellite (crystalline AsSbS 3 ) has garnered extensive attention due to its wonderful electronic and optical properties. The pressure engineering is one of the most effective methods to modulate crystal structure and physical properties of semiconductor materials. In this study, the structural behavior, optical and electrical properties of AsSbS 3 under high pressure have been investigated systematically by in situ high-pressure experiments for the first time. The monoclinic structure of AsSbS 3 remains stable up to 47.0 GPa without phase transition. The gradual lattice contraction with increasing pressure results in a continuous narrowing of the bandgap then leads to pressure-induced metallization of AsSbS 3 at 31.5 GPa. Our research presents a high-pressure strategy for tuning the crystal structure and physical properties of AsSbS 3 to expand its potential applications in electronic and optoelectronic fields.

Phosphorus-based materials with a high theoretical specific capacity and a fast charge-discharge rate are considered as promising anode materials for high energy density lithium-ion batteries (LIBs). Red phosphorus (RP) and black phosphorus (BP) are two main allotropes to be used as anode materials. However, huge volume expansion during charge-discharge processes hinders the application of RP and BP in LIBs. Composites of phosphorus and carbon-based materials have been extensively fabricated to withstand volume expansion of phosphorus and improve cycle performance. Here, composites of BP and graphite (BP-G) with three P-G mass ratios (8 : 2, 7 : 3, and 6 : 4) have been synthesized by a facile and scalable high-pressure and high-temperature (HPHT) method using RP and graphite composites (RP-G) prepared by ball milling as precursors. Their microstructure and bonding configurations have been analyzed by various characterization techniques. Among three RP-G composites, 7RP-3G exhibits the most excellent cycling stability, a high reversible capacity of 1331 mAh/g after 200 cycles at a current density of 0.78 A/g. However, RP-G composites show poor stability at high current densities. Among three BP-G composites, 6BP-4G shows the best cycle stability at high current densities, a reversible capacity of 634.6 mAh/g after 500 cycles at a current density of 2.6 A/g. Although, the reversible specific capacities of BP-G composites after long cycles are lower than those of RP-G, BP-G composites show more stable cycle performance than RP-G, especially at high current densities. The present work illustrates a direct and facile method to synthesize BP-G composites, and sheds light to explore new synthetic route of BP-based composites.

The phase stability of carbonates under mantle conditions is important for understanding the global carbon cycle. In this study, the Hugoniot data of a natural siderite (FeCO3) were measured up to 90 GPa using the plane-plate impact method. Two successive phase transitions were observed at 38-40 GPa and 65-69 GPa, respectively. In comparison with the static compression results, the first phase transition was identified as a spin transition, and the second is attributed to the self-redox reaction. The volume change during the self-redox transition is consistent with the reaction products of tetrairon orthocarbonate Fe4C3O12 and diamond. Using the measured Hugoniot data, we estimated the density of Fe4C3O12 along the lower mantle conditions and found it to be higher than the seismic values. Our results suggest siderite plays an important role in the deep carbon cycle.

Binary arsenic sulfide compounds have garnered significant attention owing to their wide-ranging physical properties and promising potential in the domains of electronics and optoelectronics. As a naturally abundant and historically significant semiconductor mineral, orpiment (crystalline As2S3) has encountered limited utilization in the realm of optoelectronics due to its considerable bandgap width. For orpiment with its quasi-two-dimensional layered structure, pressure is one of the most effective methods to regulate its crystal structure and physical properties. In this work, the structural behavior, optical and electrical properties of orpiment under high pressure have been investigated systematically utilizing a combination of experimental methods and theoretical calculations. The monoclinic structure of orpiment is stable up to 48 GPa without structural phase transitions involving changes in the space group occurred. The noticeable changes of lattice parameters, axial ratios, and interatomic distances above 20 GPa are ascribed to a transformation from a two-dimensional layered structure to a quasi-three-dimensional crystal framework. Continuous lattice contraction upon compression is accompanied by gradual bandgap narrowing, which leads to metallization of orpiment. The pressure-induced metallization of orpiment occurs above 40 GPa. The structural behavior, optical and electrical properties of orpiment at high pressure exhibit reversible hysteresis upon pressure release. This study offers a high-pressure approach for modulating crystal structure and physical properties of orpiment to expand its potential applications in the fields of electronics and optoelectronics.

Two-dimensional layered metal dichalcogenides have given rise to considerable interest in electronics and optoelectronics fields because of their excellent physical and chemical properties and promising applications. Tin disulfide (SnS2) is an important member of them due to its environment-friendly and resource-rich characteristics. Here, a series of in situ electrical transport experiments and photocurrent measurements under high pressure have been performed to investigate the electrical and opto-electrical properties of 4H-SnS2. With increasing pressure, the electrical resistivity of 4H-SnS2 decrease significantly, leading to a transition from semiconducting to metallic state above 58.6 GPa. The increase in pressure results in a substantial enhancement in photoelectric activity, indicating the extensive potential of utilizing pressure as a trigger for in situ optoelectronic applications. Combined with our previous results of x-ray diffraction and optical absorption at high pressure, pressure-induced structural distortion, bandgap narrowing, metallization, and enhancement of photoelectric activity of 4H-SnS2 are tunable and reversible, which are of great significance for both fundamental research and device design.

Single-crystal elastic moduli, Cij, and the B1-B2 phase transition of NaCl were investigated experimentally, using time-domain Brillouin scattering (TDBS), and theoretically, via density-functional-theory (DFT), to 41 GPa. Thus, we largely extended pressure range where Cij and elastic anisotropy of the solid are measured, including the first experimental data for the high-pressure B2 phase, NaCl-B2. NaCl-B1 exhibits a strong and growing with pressure anisotropy, in contrast to NaCl-B2. Theoretical values obtained using different advanced DFT functionals were compared with our measurements but no one could satisfactorily reproduce our experimental data for NaCl-B1 and NaCl-B2 simultaneously. For all available DFT results on the principal shear moduli and anisotropy, the deviation became pronounced when the degree of compression increased significantly. Similar deviations could be also recognized for other cubic solids having the same B1-type structure and similar bonding, such as CaO, MgO, or (Mg1-x,Fex)O. Furthermore, the available experimental data suggest that the B1-B2 phase transition of NaCl and the above mentioned compounds are governed by the Born stability criterion C44(P) - P > 0.

Davemaoite, as the third most abundant mineral in the lower mantle, constitutes significant amounts in pyrolite and mid-ocean ridge basalts. Due to its unquenchable nature, measurements by static compression techniques on physical properties of davemaoite at lower mantle conditions are rare and technically challenging, and those are essential to constrain compositions and properties of mineralogical models in the lower mantle. Here, we present Hugoniot equation of state and sound velocity of CaSiO3 glass under shock compression. The CaSiO3 glass transforms into the crystalline phase above 34 GPa and completely transforms into davemaoite above 120 GPa. Thermal equation of state and Hugoniot temperature of davemaoite have been derived from the shock wave data. The CaSiO3 glass under shcok compression has very high shock temperature. Shock wave experiments for sound velocity of CaSiO3 glass indicate that no melting is observed at Hugoniot pressure up to 117.6 GPa. We propose that the melting temperature of davemaoite should be higher than those reported theoretically by now.

Seismic anisotropy in the Earth's lower mantle likely results from a combination of elastic anisotropy and lattice preferred orientations of its main constituent minerals. As the second most abundant component of the lower mantle, ferropericlase has been widely studied, and the experimental results demonstrated, in general, a growing with pressure elastic anisotropy up to 1 Mbar. However, the unique measurements on the endmember (MgO) at comparable pressure conditions contradict the above observations and theoretical results. Here, time‐domain Brillouin scattering was applied to measure longitudinal sound velocities in single crystals of MgO compressed in diamond anvil cell. Velocities along two specific crystallographic directions, [100] and [111], were independently collected to 43 GPa. Applying the known bulk modulus, a complete set of single‐crystal elastic moduli, elastic anisotropy and aggregate shear modulus were derived. Our results revealed a steadily increasing with pressure elastic anisotropy at P > 20 GPa, consistent with the previous theoretical predictions and measurements on ferropericlase with moderate amounts of iron.

The equations of state and phase stabilities of high-entropy alloys (HEAs) under high-pressure and high-temperature conditions are of paramount importance for engineering applications. However, few reports exist on the high-pressure–temperature properties of the HfNbMoTaWV HEA system. Herein, we synthesized a NbMoTaW HEA using the vacuum arc melting method and measured its Hugoniot up to 143 GPa and ∼6200 K. A linear relationship [US = 2.61 (7) + 1.59 (5) UP] between the shock (US) and particle (UP) velocities was observed for UP > 0.7 km/s, suggesting that the NbMoTaW HEA is likely stable within the pressure–temperature range of the current study. Using the Debye–Mie–Grüneisen model and Birch–Murnaghan equation of state (EOS), we discussed the EOS of the NbMoTaW HEA. The bulk modulus (K0) and its pressure derivative (K0′) were determined to be 238 GPa and 3.3, respectively. We also found that the Hugoniot compression curve of the NbMoTaW HEA could be evaluated using the mixture rules with the Hugoniot data of the compositional elements.