Ab initio compressibility of metastable low albite: revealing a lambda-type singularity at pressures of the Earth’s upper mantle

Lacivita, Valentina; D’Arco, Philippe; Mustapha, Sami; Bernardes, Daniel Faria; Dovesi, Roberto; Erba, Alessandro; Rérat, Michel

doi:10.1007/s00269-020-01110-w

Cited by 6 publications

(4 citation statements)

References 48 publications

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“…The single-crystal bulk moduli, B sc , reported in Table 3, were not determined from fits of calculated pressurevolume data to high-order Birch-Murnaghan equations of state [332], as was customary in previous works [100,101,286,288,290,[298][299][300][301][302][303][304][305][306][307][308][309][310][311][312][313]331], since the fitting parameters were rather dependent on the range of pressure employed. Similar difficulties were found in the study of the compressibility of several minerals [333]. The computed bulk moduli were derived from the compressibility functions reported in Sections 3.5 and 3.6, which were determined from accurate six order polynomial fits to pressure-volume data in the pressure range from 0 to 5 GPa.…”

Section: Mechanical Propertiesmentioning

confidence: 92%

Mechanical Characterization of Anhydrous Microporous Aluminophosphate Materials: Tridimensional Incompressibility, Ductility, Isotropy and Negative Linear Compressibility

Colmenero

Lobato

Timón

2022

Solids

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Here, a detailed mechanical characterization of five important anhydrous microporous aluminophosphate materials (VPI-5, ALPO-8, ALPO-5, ALPO-18, and ALPO-31) is performed using first principles methods based on periodic density functional theory. These materials are characterized by the presence of large empty structural channels expanding along several different crystallographic directions. The elasticity tensors, mechanical properties, and compressibility functions of these materials are determined and analyzed. All of these materials have a common elastic behavior and share many mechanical properties. They are largely incompressible at zero pressure, the compressibilities along the three crystallographic directions being frequently smaller than 5 . Notably, the compressibilities of ALPO-5 and ALPO-31 along the three principal directions are smaller than this threshold. Likewise, the compressibilities of ALPO-18 along two directions are smaller than 5 . All of the considered materials are shear resistant and ductile due to the large bulk to shear moduli ratio. Furthermore, all of these materials have very small mechanical anisotropies. ALPO-18 exhibits the negative linear compressibility (NLC) phenomenon for external pressures in the range P = 1.21 to P = 2.70 GPa. The minimum value of the compressibility along the [1 0 0] direction, 30.9 , is encountered for P = 2.04 GPa. The NLC effect in this material can be rationalized using the empty channel structural mechanism. The effect of water molecule adsorption in the channels of ALPO-18 is assessed by studying the hydrated ALPO-18 material (ALPO-18W). ALPO-18W is much more compressible and less ductile than ALPO-18 and does not present NLC effects. Finally, the effect of aging and pressure polymorphism in the mechanical properties of VPI-5 and ALPO-5 is studied. As hydration, aging leads to significant variations in the elastic properties of VPI-5 and increases substantially its compressibility. For ALPO-5, pressure polymorphism has a small impact in its elasticity at zero pressure but a large influence at high pressure.

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Section: Mechanical Propertiesmentioning

confidence: 92%

Mechanical Characterization of Anhydrous Microporous Aluminophosphate Materials: Tridimensional Incompressibility, Ductility, Isotropy and Negative Linear Compressibility

Colmenero

Lobato

Timón

2022

Solids

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“…Not included in this paper is any treatment of isochemical variation. Isochemical variation can include order-disorder of chemical species on sites (e.g., Al and Si in plagioclase ;Carpenter, 1988), or structural flexibility (e.g., tetrahedral tilting in plagioclase; Mookherjee et al, 2016;Lacivita et al, 2020), or variation in proportions of spin states (e.g., iron in ferropericlase; Wu et al, 2013). Changes in isochemical state driven by changes in pressure or temperature can occur rapidly on the timescales of observations or natural phenomena such as seismic waves, and result in anomalous thermodynamic behaviour such as elastic softening.…”

Section: Discussionmentioning

confidence: 99%

“…Plagioclase is one phase exhibiting such anomalous properties presented in this study, in the regions where C 1 is stable (solid lines) and metastable (dotted lines). (Carpenter, 1988;Mookherjee et al, 2016;Lacivita et al, 2020). A treatment of isochemical variations in anisotropic solid solutions will be the subject of a follow up study.…”

Section: Discussionmentioning

confidence: 99%

An anisotropic equation of state for solid solutions, with application to plagioclase

Myhill

2024

Preprint

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This paper presents a framework for building anisotropic equations of state for solid solutions. The framework satisfies the connections between elastic and thermodynamic properties required by Maxwell’s reciprocal relations. It builds on a recent anisotropic equation of state for pure phases under small deviatoric stresses, adding a dependence on a vector n, whose components ni contain the molar amounts of independent endmembers in a solid solution. These endmembers may have distinct chemical compositions, site species occupancies or electronic spin states. The high albite-anorthite (Cbar1) plagioclase solid solution is used to illustrate the formulation.

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“…Since the discovery of the anomalous properties of quartz, anomalous material properties, many but not all associated with phase transitions, have been discovered in many other phases (Helgeson, 1978;Thompson & Perkins, 1981;Wadhawan, 1982;Dove, 1997;Carpenter, 2006). These include some of the most abundant phases in the Earth: feldspar (Mookherjee et al, 2016;Lacivita et al, 2020), garnet (Heinemann et al, 1997), orthopyroxene (Reynard et al, 2010), amphibole (Cámara et al, 2003), cristobalite (Yeganeh-Haeri et al, 1992) stishovite (Carpenter et al, 2000), ferropericlase (Wu et al, 2013) and CaSiO 3 perovskite (Stixrude et al, 2007). In all cases, the anomalous properties arise from the presence of one or more isochemical degrees of freedom in the crystalline structure.…”

Section: Anomalous Thermodynamic and Elastic Propertiesmentioning

confidence: 99%

A model of elastic softening and second order phase transitions in anisotropic phases, with application to stishovite and post-stishovite

Myhill

2024

Preprint

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This paper presents a Landau framework for describing instantaneous and time-dependent elastic softening in anisotropic solid solutions. As with previous Landau models, the framework minimizes a thermodynamic potential by varying isochemical parameters (q) that describe changes in structural, ordering or electronic spin state. Unlike previous models, no coupling terms are used; strain is not a parameter involved in the energy minimization, but is instead a property of the material. The framework satisfies all the connections between elastic and thermodynamic properties required by Maxwell's relations. The stishovite to post-stishovite transition is used to illustrate the validity of the formulation. It is shown that around the transition, the stishovite-post stishovite phase is auxetic in many directions and has negative linear compressibility along the long axis of the cell.

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Ab initio compressibility of metastable low albite: revealing a lambda-type singularity at pressures of the Earth’s upper mantle

Cited by 6 publications

References 48 publications

Mechanical Characterization of Anhydrous Microporous Aluminophosphate Materials: Tridimensional Incompressibility, Ductility, Isotropy and Negative Linear Compressibility

Mechanical Characterization of Anhydrous Microporous Aluminophosphate Materials: Tridimensional Incompressibility, Ductility, Isotropy and Negative Linear Compressibility

An anisotropic equation of state for solid solutions, with application to plagioclase

A model of elastic softening and second order phase transitions in anisotropic phases, with application to stishovite and post-stishovite

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