Hexagonal to cubic phase transition in YH3 under high pressure

2005 ◽  
Vol 133 (7) ◽  
pp. 477-480 ◽  
Author(s):  
T. Palasyuk ◽  
M. Tkacz
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Cubic Phase

Monoclinic phase of boron nitride appearing during the hexagonal cubic phase transition at high pressure and high temperature

1996 ◽  
Vol 68 (2) ◽  
pp. 182-184 ◽  
Author(s):  
Shigeo Horiuchi ◽  
Lian‐Long He ◽  
Mitsuko Onoda ◽  
Minoru Akaishi
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
High Temperature ◽  
Boron Nitride ◽  
Monoclinic Phase ◽  
Cubic Phase

Laser effects on phase transition for cubic Sb2O3 microcrystals under high pressure

2017 ◽  
Vol 5 (22) ◽  
pp. 5451-5457 ◽  
Author(s):  
Zhilei Sui ◽  
Shuhe Hu ◽  
Hao Chen ◽  
Chan Gao ◽  
Hao Su ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Laser Irradiation ◽  
Amorphous Phase ◽  
Tetragonal Phase ◽  
Cubic Phase ◽  
Ambient Conditions

Laser irradiation transforms Sb2O3 from the tetragonal phase into an HD-amorphous phase under high pressure and back to cubic phase from LD-amorphous phase at ambient conditions.

High pressure effect on the crystal structure of the BaTiO3

2019 ◽  
Vol 33 (30) ◽  
pp. 1950357
Author(s):  
Sakin H. Jabarov
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
High Pressure ◽  
Pressure Effect ◽  
Theoretical Calculations ◽  
Cubic Phase ◽  
Spontaneous Strain ◽  
Experimental Values ◽  
Murnaghan Equation ◽  
High Pressure Effect

Crystal structure of [Formula: see text] compound was studied using Atomistix Tool Kit software program at high pressure. It is defined that in this combination, tetragonal–cubic phase transition occurs under high pressure [Formula: see text] GPa. The character of this phase transition is explained in respect of baric dependence of spontaneous strain. Birch–Murnaghan equation is solved, compression ratio is determined. Results gained by theoretical calculations are compared with experimental values.

Effects of High Pressure on the Luminescent Properties of Nanocrystalline and Bulk Y2O3:Eu3+

2008 ◽  
Vol 8 (3) ◽  
pp. 1404-1409 ◽  
Author(s):  
X. Bai ◽  
H. W. Song ◽  
B. B. Liu ◽  
Y. Y. Hou ◽  
G. H. Pan ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Surface Energy ◽  
Relative Intensity ◽  
Monoclinic Phase ◽  
Local Environment ◽  
Luminescent Properties ◽  
Cubic Phase ◽  
Spectral Changes ◽  
20 Nm

High pressure-induced spectral changes in a 20-nm cubic nanocrystalline yttria doped with europium and its corresponding bulk were studied in the range of 550–750 nm, corresponding to the 5D0 → 7FJ (J = 0–4) transitions. The results demonstrate that the bulk Y2O3 underwent phase transition from the cubic phase to the monoclinic phase as the pressure increased to 15 GPa, while the 20-nm nanocrystals did not. This can be concluded from the fact that the 5D0 → 7F0 line and the three 5D0 → 7F1 sublines originating from the cubic phase disappeared, while another group of 5D0 → 7F0 and 5D0 → 7F1 lines appeared. In addition, the relative intensity of the peak around 630 nm to that around 611 nm varied obviously as the pressure surpassed 15 GPa. The variations in the nanocrystals were more sluggish in comparison to those in the bulk, indicating that the nanocrystalline yttria had improved compressibility, which is attributed to an increased surface energy in nanocrystals. The local environment surrounding luminescent Eu3+ in the nanocrystals and the bulk both became more disordered with the increase of the pressure. The phase transition from the cubic to the monoclinic is irreversible.

scholarly journals Pressure-induced phase transitions and superconductivity in a black phosphorus single crystal

2018 ◽  
Vol 115 (40) ◽  
pp. 9935-9940 ◽  
Author(s):  
Xiang Li ◽  
Jianping Sun ◽  
Prashant Shahi ◽  
Miao Gao ◽  
Allan H. MacDonald ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Single Crystal ◽  
Transport Properties ◽  
Density Functional ◽  
Black Phosphorus ◽  
Cubic Phase ◽  
Superconducting Transition ◽  
Quantum Oscillations ◽  
Mr Effect

We report a thorough study of the transport properties of the normal and superconducting states of black phosphorus (BP) under magnetic field and high pressure with a large-volume apparatus that provides hydrostatic pressure to induce transitions from the layered A17 phase to the layered A7 phase and to the cubic phase of BP. Quantum oscillations can be observed atP≥ 1 GPa in both resistivity and Hall voltage, and their evolutions with pressure in the A17 phase imply a continuous enlargement of Fermi surface. A significantly large magnetoresistance (MR) at low temperatures is observed in the A7 phase that becomes superconducting below a superconducting transition temperatureTc∼ 6–13 K.Tcincreases continuously with pressure on crossing the A7 to the cubic phase boundary. The strong MR effect can be fit by a modified Kohler’s rule. A correlation betweenTcand fitting parameters suggests that phonon-mediated interactions play dominant roles in driving the Cooper pairing, which is further supported by our density functional theory (DFT) calculations. The change of effective carrier mobility in the A17 phase under pressure derived from the MR effect is consistent with that obtained from the temperature dependence of the quantum oscillations. In situ single-crystal diffraction under high pressure indicates a total structural reconstruction instead of simple stretching of the A17 phase layers in the A17-to-A7-phase transition. This finding helps us to interpret transport properties on crossing the phase transition under high pressure.

scholarly journals Fe-doped effects on phase transition and electronic structure of CeO2 under compressed conditions from ab initio calculations

2021 ◽  
Vol 127 (10) ◽  
Author(s):  
Karnchana Sathupun ◽  
Komsilp Kotmool ◽  
Prutthipong Tsuppayakorn-aek ◽  
Prayoonsak Pluengphon ◽  
Arnab Majumdar ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Electronic Structure ◽  
Ab Initio ◽  
Orthorhombic Phase ◽  
Cubic Phase ◽  
Fe Doping ◽  
Lattice Constants ◽  
High Pressure Phase Transition ◽  
Average Bond

AbstractAb initio study of high-pressure phase transition and electronic structure of Fe-doped CeO2 with Fe concentrations of 3.125, 6.25, and 12.5 at% has been reported. At a constant-pressure consideration, the lattice constants and the volume of the supercell were decreased with an increasing concentration of Fe. The average bond length of Fe–O is lower than that of Ce–O. As a result, Fe doping induces the reduced volume of the cell, which is in good agreement with previous experiments. At high pressure (~ 30 GPa), it was found that the transition pressure from the fluorite to the cotunnite orthorhombic phase decreases at a higher concentration of Fe, indicating that the formation energy of the compound is induced by Fe-doping. Furthermore, compression leads to interesting electronic properties too. Under higher pressures, the bandgap increases in the cubic structure under compression and then suddenly plummets after the transition to the orthorhombic phase. The 3d states of Fe mainly induced the impurity states in the bandgap. In both the undoped and Fe-doped systems, the bandgap increased in the cubic phase at high pressure, while the gap and p-d hybridization decrease in the orthorhombic phase.

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