Dielectric Materials with Hyperordered Structures

Dielectric materials with “hyperordered structures” are introduced in this section. Dielectric materials are one of the key ingredients in modern electronics, as they are used in capacitors, actuators, frequency filters, and nonvolatile memories in various devices. Recent rapid growth of information and communication technologies and power electronics has inspired vital research into the development of novel dielectric materials with high permittivity, which can boost miniaturization of electronic devices and improve the energy storage density of capacitors. A conventional way to explore high-permittivity dielectrics is to design the bulk property of materials by means of ferroelectric phase transition. Many experimental and theoretical findings, however, have suggested that imperfections of materials sometimes give rise to an extraordinarily large dielectric response, as represented by relaxors. Although individual investigations are still underway, there seems to be something beyond imperfection underlying the design of high-permittivity dielectrics, namely “hyperordered structures” (HOSs). Section 13.1 provides an overview of the fundamentals of dielectric materials. Then, Sect. 13.2 introduces several conventional concepts for designing the permittivity of homogeneous dielectric materials. Next, inhomogeneous systems that show high permittivity greater than the homogeneous systems are described in Sect. 13.3. Section 13.4 discusses one potential HOS candidate in dielectric materials, electron-pinned defect dipoles, which are the extended local structures of large polarizability that form around heterovalent ions introduced to a bulk matrix.