Is it topological? A new materials database has the answer

How will we make our electronics smarter, faster, and more resilient? One idea is to use materials that are topological.

Topology is a branch of mathematics that studies shapes that can be manipulated. If a donut were made of rubber, it could be twisted and squeezed into a completely new shape, such as a coffee mug, while retaining a key trait, such as its center hole. The hole is a robust trait.

Scientists have applied concepts of topology to the discovery of materials with similar electronic properties. In 2007, researchers predicted the first electronic topological insulators that behave in ways that areologically protected or persistent in the face of disruptions.

Scientists have been searching for more topological materials to build better, more robust electronic devices. Until recently, only a few were identified, and were assumed to be rare.

If you know how to look for them, topological materials are everywhere.

The team, led by Nicolas Regnault of the cole Normale Supérieure Paris, used multiple supercomputers to map the electronic structure of more than 96,000 natural objects. They applied filters to find out what kind of traits exist in each structure.

They found that 90 percent of all known structures have at least one topological property, and more than 50 percent of naturally occurring materials have some sort of topological behavior.

The co-lead of the study says that topology is everywhere.

The newly identified materials have been compiled into a new, freely accessible Topological Materials Database. With this new library, scientists can quickly search materials of interest for any topological properties they might hold, and harness them to build ultra-low-power transistors, new magnetic memory storage, and other devices with robust electronic properties.

The paper includes co-lead authors Maia Vergniory of the Donostia International Physics Center and Luis Elcoro of the University of Basque Country.

Beyond intuition.

A desire to speed up the traditional search for topological materials was the motivation for the new study.

The way the original materials were found was through chemical intuition. It seemed that intuition wasn't getting us very far.

They used an efficient and systematic method to root out signs of topology, or robust electronic behavior, in all known crystalline structures.

The Inorganic Crystal Structure Database, or ICSD, is a repository where researchers enter the atomic and chemical structures of materials that they have studied. Materials found in nature and those manipulated in the lab are included in the database. The ICSD is the largest database of materials in the world with over 193,000 crystals.

The team downloaded the entire ICSD, and after performing some data cleaning to weed out structures with corrupted files or incomplete data, they were left with just over 96,000 processable structures. To create a map of the material's electronic structure, they performed a set of calculations based on fundamental knowledge of the chemical composition of the material.

The team was able to efficiently carry out the complicated calculations for each structure using multiple supercomputers, which they then employed to perform a second set of operations, this time to screen for various known topological phases, or persistent electrical behavior in each crystal material.

"We are looking for signatures in the electronic structure in which certain robust phenomena should occur in this material."

The team quickly discovered a large number of materials that are naturally topological, without any experimental manipulation, as well as materials that can be manipulated, for instance with light or chemical doping, to exhibit some sort of robust electronic behavior. Some materials contained more than one state when exposed to certain conditions.

Topological phases of matter in 3D solid-state materials have been proposed as places for observing and manipulating exotic effects, including the interconversion of electrical current and electron spin.

The new database of the team reveals a lot of new materials to explore.

More information: Maia G. Vergniory et al, All Topological Bands of All Non-Magnetic Stoichiometric Materials, Science (2022). DOI: 10.1126/science.abg9094. www.science.org/doi/10.1126/science.abg9094 Journal information: Science Citation: Is it topological? A new materials database has the answer (2022, May 19) retrieved 19 May 2022 from https://phys.org/news/2022-05-topological-materials-database.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.