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Rational design of inorganic dielectric materials with expected permittivity.

Xie C, Oganov AR, Dong D, Liu N, Li D, Debela TT - Sci Rep (2015)

Bottom Line: It is found that functional structure blocks (FSBs) are helpful in rational design of inorganic dielectrics with expected permittivity.To achieve this, coordination polyhedra are parameterized as FSBs and a simple empirical model to evaluate permittivity based on these FSB parameters is proposed.Using this model, a wide range of examples including ferroelectric, high/low permittivity materials are discussed, resulting in several candidate materials for experimental follow-up.

View Article: PubMed Central - PubMed

Affiliation: International Center for Materials Discovery, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, P.R. China.

ABSTRACT
Techniques for rapid design of dielectric materials with appropriate permittivity for many important technological applications are urgently needed. It is found that functional structure blocks (FSBs) are helpful in rational design of inorganic dielectrics with expected permittivity. To achieve this, coordination polyhedra are parameterized as FSBs and a simple empirical model to evaluate permittivity based on these FSB parameters is proposed. Using this model, a wide range of examples including ferroelectric, high/low permittivity materials are discussed, resulting in several candidate materials for experimental follow-up.

No MeSH data available.


Crystal structures of MgF2 and BeF2.(a)  MgF2 constructed from MgF4 coordination polyhedra; (b)  BeF2 constructed from BeF4 coordination polyhedra. Blue spheres denote F atoms, brown spheres denote Mg atoms, and green spheres denote Be atoms.
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f5: Crystal structures of MgF2 and BeF2.(a) MgF2 constructed from MgF4 coordination polyhedra; (b) BeF2 constructed from BeF4 coordination polyhedra. Blue spheres denote F atoms, brown spheres denote Mg atoms, and green spheres denote Be atoms.

Mentions: For the design of low-permittivity materials, we can immediately expect that permittivity of an oxide can be decreased by replacing O with F (see Table 1). Experimentally, SiF4 material with SiF4 tetrahedra has much lower permittivity than quartz2627. In a similar way, we can expect that and values of MgF4 coordination polyhedron may be much lower than those of MgO4 polyhedron. Therefore, we try to design low-permittivity MgF2 material with MgF4 coordination polyhedron. We constructed a new MgF2 phase (Fig. 5(a)) with very low permittivity using SiO2 structure (cristobalite) with SiO4 tetrahedra (detailed structural information can be found as Supplementary Table IIIs). The static permittivity of MgF2 (2.5) is much lower than that of quartz (3.927) and comparable to most low-permittivity polymers. The dynamical and mechanical stability of MgF2 was verified by phonon and elastic constants calculations (see Supplementary Fig. 1s and Table IVs). The enthalpy of MgF2 phase is only 0.1 eV/atom higher than that of the most stable MgF2 structure (P42/mnm phase). Moreover, this inorganic material may have a better mechanical strength than polymers (see Supplementary Table IVs). This suggests that MgF2 may be synthesized and tested as a potential low-permittivity material.


Rational design of inorganic dielectric materials with expected permittivity.

Xie C, Oganov AR, Dong D, Liu N, Li D, Debela TT - Sci Rep (2015)

Crystal structures of MgF2 and BeF2.(a)  MgF2 constructed from MgF4 coordination polyhedra; (b)  BeF2 constructed from BeF4 coordination polyhedra. Blue spheres denote F atoms, brown spheres denote Mg atoms, and green spheres denote Be atoms.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663754&req=5

f5: Crystal structures of MgF2 and BeF2.(a) MgF2 constructed from MgF4 coordination polyhedra; (b) BeF2 constructed from BeF4 coordination polyhedra. Blue spheres denote F atoms, brown spheres denote Mg atoms, and green spheres denote Be atoms.
Mentions: For the design of low-permittivity materials, we can immediately expect that permittivity of an oxide can be decreased by replacing O with F (see Table 1). Experimentally, SiF4 material with SiF4 tetrahedra has much lower permittivity than quartz2627. In a similar way, we can expect that and values of MgF4 coordination polyhedron may be much lower than those of MgO4 polyhedron. Therefore, we try to design low-permittivity MgF2 material with MgF4 coordination polyhedron. We constructed a new MgF2 phase (Fig. 5(a)) with very low permittivity using SiO2 structure (cristobalite) with SiO4 tetrahedra (detailed structural information can be found as Supplementary Table IIIs). The static permittivity of MgF2 (2.5) is much lower than that of quartz (3.927) and comparable to most low-permittivity polymers. The dynamical and mechanical stability of MgF2 was verified by phonon and elastic constants calculations (see Supplementary Fig. 1s and Table IVs). The enthalpy of MgF2 phase is only 0.1 eV/atom higher than that of the most stable MgF2 structure (P42/mnm phase). Moreover, this inorganic material may have a better mechanical strength than polymers (see Supplementary Table IVs). This suggests that MgF2 may be synthesized and tested as a potential low-permittivity material.

Bottom Line: It is found that functional structure blocks (FSBs) are helpful in rational design of inorganic dielectrics with expected permittivity.To achieve this, coordination polyhedra are parameterized as FSBs and a simple empirical model to evaluate permittivity based on these FSB parameters is proposed.Using this model, a wide range of examples including ferroelectric, high/low permittivity materials are discussed, resulting in several candidate materials for experimental follow-up.

View Article: PubMed Central - PubMed

Affiliation: International Center for Materials Discovery, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, P.R. China.

ABSTRACT
Techniques for rapid design of dielectric materials with appropriate permittivity for many important technological applications are urgently needed. It is found that functional structure blocks (FSBs) are helpful in rational design of inorganic dielectrics with expected permittivity. To achieve this, coordination polyhedra are parameterized as FSBs and a simple empirical model to evaluate permittivity based on these FSB parameters is proposed. Using this model, a wide range of examples including ferroelectric, high/low permittivity materials are discussed, resulting in several candidate materials for experimental follow-up.

No MeSH data available.