Research Highlights

Data-mining our Way to Better Nanoparticle Structures

5/28/2024 | Simon Billinge (Columbia University)

Crystallography has given us the positions of atoms in crystals for 100 years, but nano-particles require a radical rethink in approach. They form interesting non-space-filling structures that we want to synthesize and control for advanced devices, but how to accurately determine the 3D atomic arrangements?

Teaching a Machine to See Symmetry Where We Can’t

5/28/2024 | Daniel Hsu, Qiang Du, Simon Billinge (Columbia University)

Atoms typically arrange themselves in symmetric arrangements making patterns. The first step in any structure solution is determining these symmetries from the diffraction data. But in typical nanoparticle data the underlying symmetries are hidden.

Control of Electronic Properties of MXenes

5/28/2024 | Simon Billinge (Columbia University)

Over the past decade, graphene and other two-dimensional (2D) materials opened new horizons for research, from miniaturizing electronic devices to creating wearable electronics and developing new methods for water desalination and purification. 2D transition metal carbides (MXenes) are among the latest additions.

The Mathematics of Finding Atoms in Nanoparticles

5/28/2024 | Simon Billinge (Columbia University)

When atoms arrange themselves in crystals, x-ray crystallography can be used to find them. In nanostructures, atoms are much harder to find.

A New View of Grain Boundary Migration in Polycrystals

5/22/2024 | G. Rohrer, K. Dayal (Carnegie Mellon University) A. Krause (University of Florida)

Grain boundary migration during annealing is an important process because of the role it plays in determining the microstructure and properties of polycrystalline metals and ceramics.  We have used high energy x-ray diffraction microscopy to image the microstructure of α-Fe, an ideal model for commercially important steels, before and after a 600 °C anneal.

Design Principles for Sodium Superionic Conductors

5/17/2024 | Yifei Mo (University of Maryland)

Motivated by the high-performance solid-state lithium batteries enabled by lithium superionic conductors, sodium superionic conductor materials have great potential to empower sodium batteries with high energy, low cost, and sustainability. A critical challenge lies in designing and discovering sodium superionic conductors with high ionic conductivities to enable the development of solid-state sodium batteries.

Anomalously Abrupt Switching of Wurtzite-structured Ferroelectrics

5/14/2024 | Geoff Brennecka (Colorado School of Mines) Jon-Paul Maria (Penn State University)

We have extended the classic KAI model to capture scenarios in which significant growth and impingement occur while nucleation rate is increasing. This new approach collapses to the classic KAI model under conditions of pre-existing nuclei, constant or decreasing nucleation rate while for the first time enabling quantitative description of processes in which growth and impingement precede peak nucleation.

Design Principles for Wurtzite-type Ferroelectrics

5/14/2024 | Geoff Brennecka and Prashun Gorai (Colorado School of Mines)

Low-energy compute-in-memory architectures promise to reduce global energy demand for computation and data storage. Wurtzite-type ferroelectrics such as (Al,Sc)N alloy offer potential advantages in both performance and integration with existing semiconductor processes, but at present, all known wurtzite-type ferroelectrics require excessively large operating voltages for polarization reversal. We report a large-scale computational search among multinary compounds for new materials with polarization-switching barriers lower than AlN while maintaining large breakdown fields.

Interface-Tuning of Ferroelectricity and Quadruple-Well State in CuInP2S6 via Ferroelectric Oxide

5/14/2024 | Xia Hong (University of Nebraska-Lincoln) Li Yang (Washington University in St. Louis)

Layered van der Waals CuInP2S6 (CIPS) exhibits room-temperature ferroelectricity with unconventional quadruple-well states. The relatively low Curie temperature (TC) and lack of nanoscale polarization control imposes major challenges for its technological implementation.

Electrostatic Moiré Potential from Twisted Hexagonal Boron Nitride Layers

5/14/2024 | Xiaoqin Elaine Li and Keji Lai (U. TX-Austin) Li Yang (Washington U.)

The central goal of this DMREF project is to search for and realize artificial multiferroic materials consisting of van der Waals (vdW) material building blocks. Hexagonal boron nitride (hBN) is widely used in building vdW heterostructures as encapsulation layers, tunneling barriers.

Designing Materials to Revolutionize and Engineer our Future (DMREF)