First-Principles Calculations of Structural, Elastic and Electronic Properties of Tetragonal HfO
                    <sub>2</sub>
                    under Pressure

Liu, Qi‐Jun; Liu, Zheng‐Tang; Feng, Li

doi:10.1088/0253-6102/56/4/31

Cited by 7 publications

(6 citation statements)

References 41 publications

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“…Hill has shown that the Voigt and Reuss averages are limits and suggested that the actual effective B and G elastic moduli can be approximated by the arithmetic mean of the two bounds [59]. Young's (E) modulus and Poisson's ratio (ν) are calculated with the expressions [61,62]:…”

Section: B Elastic Propertiesmentioning

confidence: 99%

β−Bi2O3under compression: Optical and elastic properties and electron density topology analysis

et al. 2016

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We report a joint experimental and theoretical study of the optical properties of tetragonal bismuth oxide (β-Bi 2 O 3 ) at high pressure by means of optical absorption measurements combined with ab initio electronic band structure calculations. Our results are consistent with previous results that show the presence of a second-order isostructural phase transition in Bi 2 O 3 (from β to β ) around 2 GPa and a phase transition above 15 GPa combined with a pressure-induced amorphization above 17-20 GPa. In order to further understand the pressure-induced phase transitions and amorphization occurring in β-Bi 2 O 3 , we theoretically studied the mechanical and dynamical stability of the tetragonal structures of β-and β -Bi 2 O 3 at high pressure through calculations of their elastic constants, elastic stiffness coefficients, and phonon dispersion curves. The pressure dependence of the elastic stiffness coefficients and phonon dispersion curves confirms that the isostructural phase transition near 2 GPa is of ferroelastic nature. Furthermore, a topological study of the electron density shows that the ferroelastic transition is not caused by a change in number of critical points (cusp catastrophe), but by the equalization of the electron densities of both independent O atoms in the unit cell due to a local rise in symmetry. Finally, from theoretical simulations, β -Bi 2 O 3 is found to be mechanically and dynamically stable at least up to 26.7 GPa under hydrostatic conditions; thus, the pressure-induced amorphization reported above 17-20 GPa in powder β -Bi 2 O 3 using methanol-ethanol-water as pressure-transmitting medium could be related to the frustration of a reconstructive phase transition at room temperature and the presence of mechanical or dynamical instabilities under nonhydrostatic conditions.

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Section: B Elastic Propertiesmentioning

confidence: 99%

β−Bi2O3under compression: Optical and elastic properties and electron density topology analysis

et al. 2016

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“…64,65 On the other hand, Hill has shown that the Voigt and Reuss averages are limits and suggested that the actual effective B and G elastic moduli can be approximated by the arithmetic mean of the two bounds. 58 The Young (E) modulus and the Poisson's ratio () are calculated with the expressions: 66,67…”

Section: Dc-mentioning

confidence: 99%

High-pressure study of the structural and elastic properties of defect-chalcopyrite HgGa2Se4

Gomis¹,

Vilaplana²,

Manjón³

et al. 2013

Journal of Applied Physics

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In this work, we focus on the study of the structural and elastic properties of mercury digallium selenide (HgGa 2 Se 4) which belongs to the family of AB 2 X 4 ordered-vacancy compounds with tetragonal defect chalcopyrite structure. We have carried out high-pressure x-ray diffraction measurements up to 13.2 GPa. Our measurements have been complemented and compared with total-energy ab initio calculations. The equation of state and the axial compressibilities for the lowpressure phase of HgGa 2 Se 4 have been experimentally and theoretically determined and compared to other related ordered-vacancy compounds. The theoretical cation-anion and vacancy-anion distances in HgGa 2 Se 4 have been determined. The internal distance compressibility in HgGa 2 Se 4 has been compared with those that occur in binary HgSe and eÀGaSe compounds. It has been found that the Hg-Se and Ga-Se bonds behave in a similar way in the three compounds. It has also been found that bulk compressibility of the compounds decreases following the sequence "e-GaSe > HgGa 2 Se 4 > HgSe." Finally, we have studied the pressure dependence of the theoretical elastic constants and elastic moduli of HgGa 2 Se 4. Our calculations report that the low-pressure phase of HgGa 2 Se 4 becomes mechanically unstable above 13.3 GPa. V

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“…70,71 On the other hand, Hill has shown that the Voigt and Reuss averages are limits and suggested that the actual effective B and G elastic moduli can be approximated by the arithmetic mean of the two bounds. 72 The Young (E) modulus and the Poisson's ratio ( ) are given by 74,75 …”

Section: Elastic Propertiesmentioning

confidence: 99%

High-pressure structural and elastic properties of Tl2O3

Gomis

Santamarı́a-Pérez

Ruiz‐Fuertes

et al. 2014

Journal of Applied Physics

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High pressure transport, structural, and first principles investigations on the fluorite structured intermetallic, PtAl2 J. Appl. Phys. 111, 013507 (2012) The structural properties of Thallium (III) oxide (Tl 2 O 3 ) have been studied both experimentally and theoretically under compression at room temperature. X-ray powder diffraction measurements up to 37.7 GPa have been complemented with ab initio total-energy calculations. The equation of state of Tl 2 O 3 has been determined and compared to related compounds. It has been found experimentally that Tl 2 O 3 remains in its initial cubic bixbyite-type structure up to 22.0 GPa. At this pressure, the onset of amorphization is observed, being the sample fully amorphous at 25.2 GPa. The sample retains the amorphous state after pressure release. To understand the pressure-induced amorphization process, we have studied theoretically the possible high-pressure phases of Tl 2 O 3 . Although a phase transition is theoretically predicted at 5.8 GPa to the orthorhombic Rh 2 O 3 -II-type structure and at 24.2 GPa to the orthorhombic a-Gd 2 S 3 -type structure, neither of these phases were observed experimentally, probably due to the hindrance of the pressure-driven phase transitions at room temperature. The theoretical study of the elastic behavior of the cubic bixbyite-type structure at high-pressure shows that amorphization above 22 GPa at room temperature might be caused by the mechanical instability of the cubic bixbyite-type structure which is theoretically predicted above 23.5 GPa. V C 2014 AIP Publishing LLC. [http://dx

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First-Principles Calculations of Structural, Elastic and Electronic Properties of Tetragonal HfO ₂ under Pressure

Cited by 7 publications

References 41 publications

β−Bi2O3under compression: Optical and elastic properties and electron density topology analysis

β−Bi2O3under compression: Optical and elastic properties and electron density topology analysis

High-pressure study of the structural and elastic properties of defect-chalcopyrite HgGa2Se4

High-pressure structural and elastic properties of Tl2O3

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First-Principles Calculations of Structural, Elastic and Electronic Properties of Tetragonal HfO 2 under Pressure

Cited by 7 publications

References 41 publications

β−Bi2O3under compression: Optical and elastic properties and electron density topology analysis

β−Bi2O3under compression: Optical and elastic properties and electron density topology analysis

High-pressure study of the structural and elastic properties of defect-chalcopyrite HgGa2Se4

High-pressure structural and elastic properties of Tl2O3

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Product

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First-Principles Calculations of Structural, Elastic and Electronic Properties of Tetragonal HfO ₂ under Pressure