Topological Materials Are Everywhere – New Database Reveals Over 90,000

More than 90,000 known materials with electrical characteristics that remain unaffected by disruption are shown by this searchable tool.

What will it take to make our electronics smarter, faster, and more durable? One possibility is to construct them using topological materials.

Topology is a discipline of mathematics that analyzes shapes that can be twisted or changed without losing important qualities. A typical example is a donut: A donut might be twisted and compressed into a whole new shape, such as a coffee mug, if it were made of rubber, while keeping a critical feature: its center hole, which assumes the shape of the cup's handle. In this situation, the hole is a topological property that is resistant to specific deformations.

Scientists have recently applied topological notions to the development of materials with similar strong electrical characteristics. Researchers anticipated the first electronic topological insulators in 2007, which are materials in which electrons behave in a "topologically protected" or persistent manner in the face of certain disruptions.

Since then, scientists have been looking for new topological materials in order to build better, more durable electrical gadgets. Only a few of these compounds had been identified until recently, and they were thought to be extremely rare.

Topological materials, according to experts at MIT and elsewhere, are found everywhere. You only need to know where to look.

The team, led by Nicolas Regnault of Princeton University and the École Normale Supérieure Paris, reports harnessing the power of multiple supercomputers to map the electronic structure of more than 96,000 natural and synthetic crystalline materials in a paper published in the journal Science on May 20, 2022. They used sophisticated filters to figure out if and what kind of topological properties each structure has.

Overall, they discovered that at least one topological trait exists in 90% of all known crystalline structures, and that more than 50% of all naturally occurring materials have some form of topological activity.

“We found there’s a ubiquity — topology is everywhere,” says Benjamin Wieder, co-lead of the work and a postdoc in the Department of Physics at MIT.

The newly discovered materials have been put into a new, freely accessible Topological Materials Database, which looks like a topological periodic table. With this new library, scientists may swiftly explore materials of interest for any topological features they may have, and use those properties to create ultra-low-power transistors, novel magnetic memory storage, and other electronic devices.

Maia Vergniory of the Donostia International Physics Center, Luis Elcoro of the University of Basque Country, Stuart Parkin and Claudia Felser of the Max Planck Institute, and Andrei Bernevig of Princeton University contributed to the paper as co-lead authors.

Beyond intuition

The goal to speed up the typical search for topological materials prompted the new study.

“The way the original materials were found was through chemical intuition,” adds Wieder. “That approach had a lot of early successes. But as we theoretically predicted more kinds of topological phases, it seemed intuition wasn’t getting us very far.”

Instead, Wieder and his colleagues used a systematic and efficient way to find indicators of topology, or stable electrical behavior, in all known crystalline formations, commonly known as inorganic solid-state materials.

The researchers used the Inorganic Crystal Structure Database, or ICSD, to conduct their research. The ICSD is a repository where researchers may input the atomic and chemical structures of crystalline materials that they have investigated. Materials found in nature, as well as those manufactured and altered in the lab, are all included in the database. With approximately 193,000 crystals whose structures have been mapped and analyzed, the ICSD is presently the world's biggest materials database.

After clearing away structures containing faulty files or insufficient data, the researchers were left with slightly over 96,000 processable structures. They calculated a map of the material's electronic structure, commonly known as the electron band structure, for each of these configurations using fundamental understanding of chemical ingredient relationships.

Using numerous supercomputers, the team was able to quickly conduct the complex computations for each structure, which they then used to undertake a second series of operations, this time to screen for various known topological phases, or persistent electrical activity in each crystal material.

“We’re looking for signatures in the electronic structure in which certain robust phenomena should occur in this material,” says Wieder, whose earlier work focused on improving and expanding the screening approach known as topological quantum chemistry.

The researchers immediately uncovered a surprising number of materials that are inherently topological and do not require any experimental modification, as well as materials that can be altered to demonstrate some form of strong electrical activity, such as using light or chemical doping. They also uncovered a few materials that, when subjected to particular circumstances, possessed many topological states.

“Topological phases of matter in 3D solid-state materials have been proposed as venues for observing and manipulating exotic effects, including the interconversion of electrical current and electron spin, the tabletop simulation of exotic theories from high-energy physics, and even, under the right conditions, the storage and manipulation of quantum information,” says Wieder.

Wieder said the team's new database now offers a plethora of novel materials to investigate for experimentalists exploring similar effects.