Researchers make a new type of quantum material with a dramatic distortion pattern

Researchers at the Department of Energy's SLAC National Accelerator Laboratory and Stanford University have created a new type of quantum material whose atomic scaffolding, or lattice, has been dramatically warped into a ...

The resulting distortions are "huge" compared to those achieved in other materials, said Woo Jin Kim, a postdoctoral researcher at the Stanford Institute for Materials and Energy Sciences (SIMES) at SLAC who led the study. "This is a very fundamental result, so it's hard to make predictions about what may or may not come out of it, but the possibilities are exciting," said SLAC/Stanford Professor and SIMES Director Harold Hwang. "Based on theoretical modeling from members of our team, it looks like the new material has intriguing magnetic, orbital and charge order properties that we plan to investigate further," he said. Those are some of the very properties that scientists think give quantum materials their surprising characteristics.

The research team described their work in a paper published in Nature today. High-rises versus octahedrons The herringbone-patterned material is the first demonstration of something called the Jahn-Teller (JT) effect in a layered material with a flat, planar lattice , like a high-rise building with evenly spaced floors. The JT effect addresses the dilemma an electron faces when it approaches an ion—an atom that's missing one or more electrons.

Illustration showing distortions in a new quantum material that were produced by an electronic tug-of-war between negatively charged cobalt ions ­and positively charged calcium ions. In what's known as the Jahn-Teller effect, each cobalt ion tries to pull calcium ions from the layers above and below it, warping the atomic lattice in the direction of the arrows in a way that had not been seen before. Credit: Woo Jin Kim/SIMES Read more

In experiments at SLAC and Stanford, researchers changed the atomic structure of the material at left, which consists of octahedral and tetrahedral layers and is known as brownmillerite, by chemically removing layers of oxygen, much as Jenga players carefully removed wooden blocks from a stack. The resulting material, right, was dramatically distorted into a herringbone pattern by an electronic tug-of-war between its layers caused by the Jahn-Teller effect. Credit: Woo Jin Kim/SIMES Read more

This illustration shows how an electronic tug-of-war between the layers of a new quantum material has warped its atomic lattice into a dramatic herringbone-like pattern. Scientists at SLAC and Stanford who created the material are just starting to explore how this 'huge' distortion affects the material's properties. Credit: Greg Stewart/SLAC National Accelerator Laboratory Read more