Title: Phenomenological studies of compositionally graded ferroelectric superlattices
Principal Investigator:
Dr Kok-Geng Lim
Introduction:
The compositionally graded ferroelectric based on a lead-free solid solution system such as BaxSr1-xTiO3 can exhibit large polarization gradients and desirable temperature-stable susceptibilities. This novel solid solution is not only in compliance with the future lead-free trend but also meets the requirement of a large piezoelectric response of ferroelectrics for modern electronic applications.
Abstract:
The compositionally graded ferroelectric based on a lead-free solid solution system such as BaxSr1-xTiO3 can exhibit large polarization gradients and desirable temperature-stable susceptibilities. This novel solid solution is not only in compliance with the future lead-free trend but also meets the requirement of a large piezoelectric response of ferroelectrics for modern electronic applications. By tailoring their composition at the atomic level, we can manipulate the physical properties and functionalities of compositionally graded ferroelectric. Hence, this research is to develop a thermodynamic model based on the Landau-Ginzburg theory to study the fundamental physical properties of compositionally graded ferroelectric superlattices by considering the interface effect. A theoretical study on the fundamental physical properties is very crucial in the fabrication of compositionally graded ferroelectric superlattices for technological applications, for instance: transducers, high permittivity dielectrics, pyroelectric sensors, piezoelectric devices, tunable ferroelectric capacitors et al.
Title: Dyonic wormhole in the Einstein-Yang-Mills-Higgs theory
Principal Investigator:
Dr Kok-Geng Lim
Introduction:
Wormholes are hypothetical compact objects that connect two distant regions in the universe which allow time travel or interstellar travel. For instance, the traversable wormhole depicted in Christopher Nolan’s science fiction movie “Interstellar”. The first postulated wormhole in General Relativity (GR) is the Einstein-Rosen (ER) bridge, arising when the structure of spacetime is curved and strongly bent by gravity.
Abstract:
Wormholes are hypothetical compact objects that connect two distant regions in the universe which allow time travel or interstellar travel. For instance, the traversable wormhole depicted in Christopher Nolan’s science fiction movie “Interstellar”. The first postulated wormhole in General Relativity (GR) is the Einstein-Rosen (ER) bridge, arising when the structure of spacetime is curved and strongly bent by gravity. Recently, we have found the non-Abelian wormhole solutions supported by the phantom field in the Einstein-Yang-Mills-Higgs (EYMH) theory, which possesses the YMH hair in the presence of gravity [Phys. Rev. D 102, 124068 (2020), Phys. Rev. D 105, 084058 (2022)]. In flat space, dyon is a particle that possesses both magnetic and electrical charges. In curved spacetime, the EYMH theory also possesses gravitating dyons and dyonic black hole solutions. Hence, it is instructive to study the dyonic wormhole in the EYMH theory.