MSE Department Seminar

We address the problem of learning of classical Markov Random Fields that are widely used in material science, statistical physics, and computer science to represent structured Gibbs distributions. We introduce a new computationally efficient Interaction Screening method for learning discrete and continuous Gibbs distributions for which maximum likelihood approaches are intractable. The algorithm recovers the structure and parameters of the Hamiltonians with multi-body interactions specified in an arbitrary basis.

100 years since the discovery of ferroelectricity, this phenomenon still remains a center of intense research. The electrically switchable polarization, which is strongly coupled to the physical properties of ferroelectrics, determines the multifunctional nature of their responses to the external stimuli and underpins our ability to address a range of technological applications related to future computing.

The emergence of the two-dimensional (2D) transition metal dichalcogenides (TMDCs) ushers in a new chapter in excitonic physics. In monolayer TMDCs, the reduced screening enhances the Coulomb interaction and gives rise to strongly bound excitons with the binding energy of hundreds of meV. In addition, the valley degree of the freedom of the exciton is robust and can be accessed through chiral light. For the past few years, we have advanced our understanding of the valley contrasting excitonic physics in monolayer WSe₂ and associated van der Waals (vdW) heterostructures.

There is nothing more personal than healthcare. Health care should move from its current reactive and disease-centric system to a personalized, predictive, preventative, and participatory model with a focus on disease prevention and health promotion. As the world marches into the era of the Internet of Things (IoT) and 5G wireless, technology renovation enables the industry to offer a more individually tailored approach to healthcare with better health outcomes, higher quality, and lower cost.

Owing to the unique interface coupling and vertical interfacial strain, vertical heteroepitaxial nanocomposite films can be used to design enhanced and/or novel functionalities. In this talk, I will discuss our efforts to design, synthesize and characterize a variety of epitaxial vertical nanocomposite thin films. Nanopillar feature size has been found to be a critical parameter to control strain, defects and vertical interface density.

EFRC WastePD (Center for Performance and Design of Nuclear Waste Forms and Containers) is a multi-institute energy frontier research center established by Department of Energy in 2016 with the key mission to understand the fundamental mechanisms of waste form performance and apply that understanding to develop tools for design of waste forms with improved performance. Key performance parameter of nuclear waste forms is degradation by interaction with aqueous environment (corrosion) over long periods of time.

Long wavelength longitudinal phonons can propagate in liquids, but whether transverse phonons exist in liquids has been debated since the 1970s. The classic hydrodynamic theory refutes the existence of the latter because the transverse current fluctuation does not directly couple with the density fluctuation and the Brillouin zone is not well-defined. However, such arguments fail to describe the viscoelastic response of liquids and glasses. Recently, we have developed a viscoelastic hydrodynamic theory by incorporating both viscoelasticity and anisotropy.

Degradable polymers are used widely in medical devices and regenerative medicine.  Maturing capabilities in additive manufacturing coupled with advances in orthogonal chemical functionalization methodologies have enabled a rapid evolution of defect specific form factors and strategies for designing and creating bioactive scaffolds.

Symmetry lies at the heart of the laws of nature and determines material properties at the fundamental level. We all know that breaking the inversion symmetry is directly mapped into materials properties by inducing a plethora of effects such as dielectric polarisation along with pyro- and ferroelectricity, piezoelectricity, bulk photovoltaic effect, electro-optic effect and second harmonic generation, etc. Material symmetry in chiefly determined by its pristine crystallographic structure, but external stimuli can also lower symmetry or even break the inversion symmetry.

Synthetic polymers are among the most important materials to modern society. The development of living and controlled polymerization methodologies have enabled the synthesis of precise macromolecular architectures with tailored polymer properties for diverse applications. This presentation will discuss the design, development, and use of organic photoredox catalysts in organocatalyzed atom transfer radical polymerization for the synthesis of well-defined polymers.