The Benedek group uses theory and first-principles calculations to design, predict and understand the structures and properties of functional materials, especially complex oxides.
Fundamental Solid-State Chemistry of Complex Oxides and Related Materials
Although a major focus of our research is nonequilibrium materials science, a fundamental understanding of structural and solid-state chemistry lies at the heart of almost all our work. We are particularly interested in the ABO3 perovskite family of oxides (including layered perovskites) shown in the figure below, a large and technologically important family of materials. Recent work has focused on understanding and exploiting new ferroelectric mechanisms to create multifunctional materials.
- Theory and neutrons combine to reveal a family of layered perovskites without inversion symmetry
- ‘Ferroelectric metals’ reexamined: Fundamental mechanisms and design considerations for new materials
- Understanding ferroelectricity in layered perovskites: new ideas and insights from theory and experiments
- Origin of ferroelectricity in a family of polar oxides: The Dion—Jacobson phases
- Why are there so few perovskite ferroelectrics?
Linking Structure and Chemistry to Fast Ionic Transport in Complex Oxides
The strong coupling of structural distortions in perovskites to functional properties and the formulation of design rules based on these structure-property relationships has allowed researchers to make tremendous progress in rationally designing perovskites with particular electronic or magnetic properties. The discovery of similar relationships for ionic transport could be transformational in advancing our fundamental understanding of ionic transport phenomena in layered perovskites, and in complex oxides generally. Our group has been working to make connections between specific structural distortions and ionic transport in particular families of layered perovskites (commonly used as cathode materials for Solid Oxide Fuel Cells).
Frontiers of Thermal Transport: Unlocking the Potential of Complex Oxides
Our fundamental understanding of the phonon properties of materials has always lagged behind that of the electronic properties; this knowledge gap severely limits our ability to design materials with target thermal transport properties. This is particularly true of complex oxides. We use first-principles DFT in combination with the phonon Boltzmann transport approach to unravel the microscopic mechanisms of thermal transport in complex oxides, particularly perovskites. A major goal of our work in this area is to establish the fundamental foundation necessary to enable the design of materials with targeted and dynamically controllable thermal transport properties.
- “Interplay between phonons and anisotropic elasticity drives negative thermal expansion in PbTiO3“