Being a best known thermoelectric material and topological insulator at ambient condition, magic bismuth telluride (${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$) under pressure transforms into several superconducting phases, whose structures remain unsolved for decades. Here, we have solved the two long-puzzling low high-pressure phases as seven- eightfold monoclinic structures, respectively, through particle-swarm optimization technique on crystal structure prediction. Above 14.4 GPa,...

Bulk quantities of nitrogen-rich graphitic carbon nitride are synthesized via a facile reactive pyrolysis process with mixture melamine and cyanuric chloride as the molecular precursors. Scanning electron microscopy transmission studies show that micrometer-sized hollow vessels high aspect ratios have been successfully elaborated without designed addition any catalyst or template. The composition prepared determined by combustion method is C(3)N(4.91)H(1.00)O(0.22), N/C ratio to be 1.64,...

Two-dimensional tin selenide (SnSe) nanosheets were synthesized using a plasma-assisted direct current arc discharge method. The structural characterization indicates that the are single-crystalline with an average thickness of ~25 nm and lateral dimension 500 nm. high pressure behaviors as-synthesized SnSe investigated by in situ high-pressure synchrotron angle-dispersive X-ray diffraction Raman scattering up to ~30 GPa diamond anvil cells at room temperature. A second-order isostructural...

Hexagonal corundum-type indium oxide (h-In2O3) is the structure that normally exists in a high-temperature and pressure environment. This has been realised from ambient environment stable cubic (c-In2O3) using high-energy ball milling approach at room temperature, which rearrangements of InO6 polyhedral units take place via plastic deformation large defect creation during process. More interestingly, h-In2O3 as anode materials lithium-ion batteries exhibits lithium storage capabilities...

Flower-shaped undoped and Ag-doped ZnO nanocrystals have been synthesized by a hydrothermal method. The investigated x-ray powder diffraction all the particles are found to show wurtzite structure. Scanning electron microscopy high resolution transmission reveal flower-shaped structures of samples consist many pricklelike nanopetals. photoelectron spectroscopy results provide evidence that Ag ions mainly in monovalent state incorporated into lattice at Zn2+ sites. It was from UV–visible...

Sc-doped AlN (AlN:Sc) sixfold-symmetrical hierarchical nanostructures were grown by direct current (dc) arc discharge plasma method using the reaction of Al and Sc metals with N2 gas. Energy-dispersive x-ray spectroscopy, diffractometry, Raman spectra analysis clearly showed that was doped in nanostructures. The magnetization curves indicate existence room-temperature ferromagnetic behavior. saturation coercive fields (Hc) AlN:Sc are about 0.04 emu g−1 200 Oe, respectively. results reveal is...

The effects of high pressure on the structural stability melamine−boric acid adduct (C3N6H6·2H3BO3, M·2B), a three-dimensional hydrogen-bonded supramolecular architecture, were studied by in situ synchrotron X-ray diffraction (XRD) and Raman spectroscopy. M·2B exhibited compressibility strong anisotropic compression, which can be explained layerlike crystal packing. Furthermore, evolution XRD patterns spectra indicated that undergoes reversible pressure-induced amorphization (PIA) at 18 GPa....

Hexagonal and truncated hexagonal shaped MoO3 nanoplates (MoO3 HNP) were synthesized through a simple vapor-deposition method in Ar atmosphere under ambient pressure without the assistant of any catalysts. The structure morphology HNP investigated by XRD, EDX, SEM, TEM, HRTEM. results reveal that are α-MoO3 have large area surface. Raman spectrum shows significant size effect on vibrational property HNP. photoluminescence (PL) was carried out, two peaks at 351 410 nm observed spectrum. In...

Using the angle-dispersive synchrotron x-ray powder diffraction technique in a diamond anvil cell, high-pressure behaviors of antimony telluride (Sb2Te3) are explored up to 52.7 GPa at room temperature. Three phases have been observed, about 8.0 GPa, 13.2 and above 21.6 respectively. Furthermore, crystalline structures these determined as monoclinic sevenfold C2/m phase, eightfold C2/c phase disordered body-centered cubic structure (space group Im − 3m) The phase-transition sequences...

The Eu-doped yttria (Y2O3:Eu3+) has been investigated by the in situ high-pressure angle dispersive synchrotron X-ray diffraction (XRD) and photoluminescence (PL) spectroscopy. red shift intensity ratio variation of emissions with increasing pressure were observed elucidated. It was found that is related to expansion f orbit Eu3+ ascribed change crystal field under high pressure. pressure-induced changes spectrum are phase transition, which confirmed XRD pattern. two phases identified as...

Abstract The effect of fracture networks on EGS performance remains worth further investigation to guide the formulation geothermal extraction strategy. We established models that account for thermo-hydraulic-mechanical (THM) coupling and are based framework discrete network (DFN) evaluate heat in deep-seated fractured reservoir. Our numerical results reveal zones temperature, pressure, stress perturbation diffuse asynchronously during circulation injection-production, always lags behind...

The structural transformations occurring to water from low-density (LDW) high-density (HDW) regimes have been studied by Brillouin scattering for the first time at temperatures up 453 K and pressures solidification point. At ambient temperature (293 K) a discontinuity in pressure response of sound velocity is observed. Furthermore, there are evident breaks linear behavior log10 C11 versus log10(rho/rho0) when increases 0.29, 0.21, 0.19 GPa 293, 316, 353 K, respectively. It supposed indicate...

The high-pressure behavior of scandium oxide (Sc(2)O(3)) has been investigated by angle-dispersive synchrotron powder X-ray diffraction and Raman spectroscopy techniques in a diamond anvil cell up to 46.2 42 GPa, respectively. An irreversible structural transformation Sc(2)O(3) from the cubic phase monoclinic was observed at 36 GPa. Subsequent ab initio calculations for predicted transition but much lower pressure. same second 77 GPa hexagonal phase.

Single-crystal samples of the 1:1 adduct between cyanuric acid and melamine (CA.M), an outstanding case noncovalent synthesis, have been studied by Raman spectroscopy synchrotron X-ray diffraction in a diamond anvil cell up to pressures 15 GPa. The abrupt changes spectra around 4.4 GPa provided convincing evidence for pressure-induced structural phase transition. This transition was confirmed angle dispersive (ADXRD) experiments be space group change from C2/m its subgroup P2(1)/m. On...

Aluminum nitride (AlN) nanostructures have shown novel physical and chemical properties that are essential for technological applications. We report a vapor−solid growth of three-dimensional (3D) AlN urchin-like nanostructure in DC arc plasma via the direct reaction between Al vapor N2 gas without any catalyst or template. The as-prepared 3D which shapes consist numerous microdaggers with sharp tips lengths up to several micrometers widths 0.5−2 μm. A mechanism urchin was suggested explained...

Room-temperature ferromagnetism has been observed in Y-doped AlN (AlN:Y) nanorods. Our first-principle calculations have demonstrated that the AlN:Y is from Al vacancies and introduction of nonmagnetic rare-earth element Y into can significantly reduce formation energy vacancy which leads to high responsible for These findings illustrate an efficient way cation by doping elements, such as Y, leading semiconductors.

In situ characterization of phase transitions and direct microscopic observations a low-melting ionic liquid, 1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIM][BF(4)]), has been performed in detail by Raman spectroscopy. Compression [BMIM][BF(4)] was measured under hydrostatic pressure up to ~30.0 GPa at room temperature using high-pressure diamond anvil cell. With increasing, the characteristic bands displayed nonmonotonic pressure-induced frequency shifts, it is found undergo four...