UCLA led team opens ‘new avenues’ into topological insulator research

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A research team from UCLA says it has made a major step forward in developing and using topological insulators, which conduct electricity on their surface, but not in their interior.

Magnetised topological insulators could improve the energy efficiency and operating speed of computers ‘dramatically’, says the team, which offers two ways to do this. One way infuses magnetic materials into the topological insulator; the other stacks thin layers of alternating magnetic materials between the insulators.

While both methods magnetise the topological insulator, both also can disrupt the insulator’s desirable properties if the magnetism is too strong. Instead of stacking alternating layers, the team used an antiferromagnetic material in conjunction with the topological insulator, effectively cancelling out the overall magnetism. However, one atomic layer at the interface remains magnetic and this can be exploited for data storage.

“Using antiferromagnetic materials with topological insulators provides a new avenue to bring the latter material into applications, in addition to exploring new physics,” said Professor Kang Wang.

“When we combined topological insulators with antiferromagnetic layers, we found they could operate at 90K,” said post doctoral researcher Qing Lin He. “This is an enormous opportunity for opening up a totally new direction. While it’s still not room temperature, it’s a very promising way forward.”

Topological insulators may also find application in quantum computers as, when they conduct electricity, all electrons flowing in one direction have the same spin direction.

Collaborators include researchers from NIST, Stanford University and the Beijing University of Technology.