Study may lead to next-gen nanoelectronic and spintronic devices

LONDON - A new study from UCLA scientists promises to introduce new-generation nanoelectronic and spintronic devices.

Researchers from UCLA’s Henry Samueli School of Engineering and Applied Science and from the materials division of Australia’s University of Queensland show the promise of surface-conduction channels in topological insulator nanoribbons made of bismuth telluride and demonstrate that surface states in these nanoribbons are “tunable” - able to be turned on and off depending on the position of the Fermi level.

“Our finding enables a variety of opportunities in building potential new-generation, low-dissipation nanoelectronic and spintronic devices, from magnetic sensing to storage,” said Kang L. Wang.

With their large surface-to-volume ratios, these topological insulator nanoribbons significantly enhance surface conditions and enable surface manipulation by external means.

Wang and his team used thin bismuth telluride nanoribbons as conducting channels in field-effect transistor structures. These rely on an electric field to control the Fermi level and hence the conductivity of a channel.

“We have demonstrated a clear surface conduction by partially removing the bulk conduction using an external electric field,” said Faxian Xiu.

“By properly tuning the gate voltage, very high surface conduction was achieved, up to 51 percent, which represents the highest values in topological insulators.”

The new findings shed light on the controllability of the surface spin states in topological insulator nanoribbons and demonstrate significant progress toward high surface electric conditions for practical device applications.

The next step for Wang’s team is to produce high-speed devices based on their discovery.

The study is published Feb. 13 in Nature Nanotechnology. (ANI)