New way to identify and manipulate topological metals

An electron incident on a Weyl semimetal from a normal metal is transmitted into specific states in the Weyl semimetal along with a reflection that conserves momentum, energy, and spin. A net spin current with no net flow of electrons can give rise to a charge current in the Weyl semimetal. Credit: Argonne National Laboratory / Ellen Weiss

Topological materials have become a hot topic in quantum materials research, as they have potential applications for quantum information and spintronics. This is because topological materials have strange electronic states in which an electron’s momentum is connected to its spin orientation, something that can be exploited in new ways to encode and transmit information. One type of topological material, called a magnetic Weyl semimetal, is attracting interest because of its potential ability to be manipulated with magnetic fields.

A recent theory and modeling study from scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory may not only give researchers an easier way of finding Weyl semimetals, but also a way to more easily manipulate them for potential spintronic devices. By moving spins preferentially from the normal metal into the Weyl semimetal, the researchers found that the semimetal needed to find ways to accommodate electrons with particular spins in its electronic structure. The different resulting electronic states travel with different speeds, generating a charge current. (Physical Review Letters)

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