Learning Stability of AB2X6 Compounds to Guide Synthesis of Trirutile Oxides

2/21/2023 | James Rondinelli (Northwestern University), Stephen Wilson and Ram Seshadri (UCSB)

Through machine learning methods, we find that, consistent with factors determining crystallization in other structural families, geometric and bonding constraints are the most important features determining the formation of a trirutile structure.

Featureless Optimization of Material Properties for Small Data Sets in Complex Ceramics

2/21/2023 | James Rondinelli (Northwestern University)

Electronic materials that exhibit phase transitions between metastable states (e.g., metal-insulator transition materials with abrupt electrical resistivity transformations) are challenging to decode. For these materials, conventional machine learning methods display limited predictive capability due to data scarcity and the absence of features that impede model training. In this work, we developed an adaptive optimization engine that overcomes these limitations

Magnetoentropic Mapping of GaV4S8 and GaV4Se8

2/21/2023 | Stephen Wilson and Ram Seshadri (UCSB)

Here we demonstrate the utility of the magnetoentropic mapping method in combination with computational models to rapidly identify magnetic textures such as cycloids and skyrmions in uniaxial systems

From Insulator to Metal: Chemical Design of Electronic Transitions

2/17/2023 | James Rondinelli (Northwestern University)

We identified the relationship between local structural distortions, induced by chemical ordering of cations, and the interactions governing the electronic state (insulator or metal) of LaSrAlO4. The structure of this compound hosts a broad range of chemistries known to exhibit metal-to-insulator (MIT) transitions and will enable future materials design.

Evidence of a Room-temperature Quantum Spin Hall Edge State in a Higher-order Topological Insulator

2/16/2023 | Fan Zhang (University of Texas at Dallas)

Room-temperature realization of macroscopic quantum phases is one of the major pursuits in fundamental physics. A topological insulator is a material that behaves as an insulator in its interior but whose surface contains protected conducting states.

Discovery of Tunable Quantum Anomalous Hall Octet

2/16/2023 | Fan Zhang (University of Texas at Dallas)

Bernal bilayer graphene is a naturally occurring system with neither spin-orbit coupling nor moiré complex. •Quantum anomalous Hall (QAH) octet, i.e., eight states exhibiting quantum Hall effect at zero magnetic field, was theoretically predicted and experimentally observed.

Self-assembled Block Polymers with Complete Photonic Band Gaps

2/10/2023 | Glenn H. Fredrickson and Kevin D. Dorfman

We have developed a workflow that allows for theoretical prediction of photonic crystals formed from bottom-up self assembly of block polymers. Using established self-consistent field theory (SCFT) methods, we are able to predict the symmetries of stable periodic structures formed at lengths scales of 10s-100s nm by such materials. Following structure prediction, photonic band structures are predicted by solving Maxwell’s equations on the resulting periodic dielectric profile.

Controlling Supramolecular Chirality in Peptide-p-peptide Networks

2/8/2023 | J. Tovar (Johns Hopkins U.) A. Ferguson (U. Chicago)

Synthetic peptide libraries to probe chiroptical properties.We found that carbon spacers between pi-conjugated electronic units and flanking peptide sequences had a profound impact on the superstructural chirality of the nanomaterials that form after self-assembly. The origins of this control were elucidated through computational analysis. These findings are of importance for chiroptical applications such as circularly polarized luminescence.

Self-assembled Peptide-p-electron Supramolecular Polymers for Bioinspired Energy Harvesting, Transport and Management

2/8/2023 | J. Tovar, H. Katz (Johns Hopkins U.) and A. Ferguson (U. Chicago)

Organic electronics offer a route toward electronically active biocompatible soft materials capable of interfacing with biological and living systems. Discovering new organic molecules capable of high charge mobility is challenging due to the vast size of molecular design space and the multi-scale nature of charge transport that requires modeling electrons, molecules, and supramolecular assemblies.

Self-assembled Peptide-p-electron Supramolecular Polymers

2/8/2023 | A. Ferguson (U. Chicago)

Non-natural peptides containing electron-rich aromatic subunits have demonstrated the remarkable ability to spontaneously assemble into long fibers with optical and electronic responses similar to conventional silicon electronics. These molecules have the potential to serve as new biocompatible organic electronics with uses in medical interventions and clean energy.

Research Highlights