Hardness and elasticity in cubic ruthenium dioxide

Léger, Jean‐Michel; Djémia, Philippe; Ganot, F.; Haines, J.; Pereira, Altaïr Soria; Jornada, J. A. H. da

doi:10.1063/1.1401786

Cited by 39 publications

(22 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…[3,4,18,24] Covalent materials generally display high bond-bending force constants, contain highly directional bonds, and generally have high shear moduli. In an ionic material, however, the electrostatic interactions are omnidirectional, resulting in low bond-bending force constants and consequently a low shear modulus.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

Advancements in the Search for Superhard Ultra‐Incompressible Metal Borides

Levine

Tolbert

Kaner

2009

Adv Funct Materials

336

232

View full text Add to dashboard Cite

Dense transition metal borides have recently been identified as superhard materials that offer the possibility of ambient pressure synthesis compared to the conventional high pressure, high temperature approach. This feature article begins with a discussion of the relevant physical properties for this class of compounds, followed by a summary of the synthesis and properties of several transition metal borides. A strong emphasis is placed on correlating mechanical properties with electronic and atomic structure of these materials in an effort to better predict new superhard compounds. It concludes with a perspective of future research directions, highlighting some recent results and presenting several new ideas that remain to be tested.

show abstract

Section: Mechanical Propertiesmentioning

confidence: 99%

Advancements in the Search for Superhard Ultra‐Incompressible Metal Borides

Levine

Tolbert

Kaner

2009

Adv Funct Materials

336

232

View full text Add to dashboard Cite

show abstract

“…Using the correlation between the bulk modulus and the hardness, many theoretical predictions on hard materials have been made during the last few decades. However, Lèger et al [37] confirm the shear modulus (G) as the best hardness predictor for a wide variety of materials. The magnitude of G describes the resistance of a material upon shape change and plays an important role in the elasticity theory.…”

Section: Elastic Properties and Phase Stabilitymentioning

confidence: 99%

Characterization of platinum nitride from first-principles calculations

Yıldız

Akıncı

Gülseren

et al. 2009

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

We have performed a systematic study of the ground state properties of the zinc-blende, rock-salt, tetragonal, cuprite, fluorite and pyrite phases of platinum nitride by using the plane wave pseudopotential calculations within the density functional theory. The equilibrium structural parameters and bulk moduli are computed within both the local density approximation (LDA) and generalized gradient approximation (GGA). The comparison of the equation of state (EOS) calculated within the LDA for the pyrite structure with the experimental results demonstrates an excellent agreement, hence the use of the LDA rather than the GGA is essential. Complete sets of elastic moduli are presented for cubic forms. The analysis of the results reveal that the pyrite phase with PtN2 stoichiometry leads to the formation of a hard material with the shear modulus G = 206 GPa. The electronic structure of pyrite PtN2 is given, which shows a narrow indirect gap. The vibrational properties of platinum nitride are investigated in detail from lattice dynamical calculations. The calculations show that fluorite and pyrite structures are dynamically stable as well. However, the calculated vibrational modes of pyrite PtN2 do not show complete agreement with experimental Raman frequencies.

show abstract

“…16 In particular, RuO 2 is considered to be a potential ultrahard material because of its measured Knoop hardness ͑ϳ20 GPa͒ and bulk modulus ͑399 GPa͒, which is only 10% less than that of sintered diamonds. 17 Moreover, synthesized cotunnite TiO 2 has an extremely high bulk modulus of 431 GPa and is considered as the hardest oxide to date. 1 After the synthesis of cotunnite TiO 2 , scientists expected to synthesize cubic TiO 2 because it showed potential for use as a solar cell or ultrahard material.…”

mentioning

confidence: 99%

Unusual compression behavior ofTiO2polymorphs from first principles

Zhou¹,

Dong²,

Qian³

et al. 2010

Phys. Rev. B

View full text Add to dashboard Cite

The physical mechanisms behind the reduction in the bulk modulus of a high-pressure cubic TiO 2 phase are revealed by first-principles calculations. An unusual and abrupt change occurs in the dependence of energy on pressure at 43 GPa, indicating a pressure-induced phase transition from columbite TiO 2 to a modified fluorite TiO 2 with a Pca21 symmetry. Oxygen atom displacement in Pca21 TiO 2 unexpectedly reduces the bulk modulus by 34% relative to fluorite TiO 2 . This discovering provides a direct evidence for understanding the compressive properties of such groups of homologous materials.Titanium dioxide ͑TiO 2 ͒ has rich phase diagrams, namely, the rutile ͑P42/ mnm͒, anatase ͑I41/ amd͒, brookite ͑Pbca͒, columbite ͑Pbcn͒, baddeleyite ͑P21/ c͒, and cotunnite ͑Pnma͒ phases. 1-6 Due to its versatile physical and chemical properties, TiO 2 is extensively used in many industrial applications, such as high efficiency solar cells, photocatalysis, dynamic random access memory modules, and superhard materials. 7-12 The rutile and anatase phases of TiO 2 are abundant in nature. 13,14 Since the phase sequence of TiO 2 is very similar to that of other bulk materials, such as ZrO 2 and HfO 2 , it is highly expected to transform into its cubic polymorphs under pressure. 15 Modified cubic fluorite-structured RuO 2 , SnO 2 , and PbO 2 that possess a Pa3 symmetry, have been successfully synthesized. 16 In particular, RuO 2 is considered to be a potential ultrahard material because of its measured Knoop hardness ͑ϳ20 GPa͒ and bulk modulus ͑399 GPa͒, which is only 10% less than that of sintered diamonds. 17 Moreover, synthesized cotunnite TiO 2 has an extremely high bulk modulus of 431 GPa and is considered as the hardest oxide to date. 1 After the synthesis of cotunnite TiO 2 , scientists expected to synthesize cubic TiO 2 because it showed potential for use as a solar cell or ultrahard material. Ultimately, the highly anticipated cubic TiO 2 was successfully synthesized by heating anatase TiO 2 between 1900 and 2100 K in diamond-anvil cells under a pressure of 48 GPa. 18 Some ambiguities, however, remained both in experiment and in theory. For instance, the theoretical bulk modulus calculated for cubic TiO 2 in the pyrite and fluorite phases was significantly larger than that obtained during the experiments. Kim et al. 13 showed that pyrite TiO 2 is unstable because of the presence of imaginary frequencies in the phonon spectra throughout the entire pressure range, whereas fluorite TiO 2 is stable because of the absence of these imaginary frequencies under pressure. Swamy and Muddle 19 reported that pyrite TiO 2 has theoretical properties closer to the experimental values because it has a relatively lower bulk modulus. In terms of mechanical properties, however, Liang et al. 20 found a minor difference between the fluorite and pyrite phases. At the present stage, there is no theory of the cubic phase of TiO 2 , and that although there is some disagreement between existing calculations on candidate phases fluorite and pyrite, ...

show abstract

Hardness and elasticity in cubic ruthenium dioxide

Abstract: Articles you may be interested inCorrelation between hardness and elastic moduli of the ultraincompressible transition metal diborides Ru B 2 , Os B 2 , and Re B 2

Cited by 39 publications

References 18 publications

Advancements in the Search for Superhard Ultra‐Incompressible Metal Borides

Advancements in the Search for Superhard Ultra‐Incompressible Metal Borides

Characterization of platinum nitride from first-principles calculations

Unusual compression behavior ofTiO2polymorphs from first principles

Contact Info

Product

Resources

About