Visualizing Tailored Spin Phenomena in a Reduced-Dimensional Topological Superlattice.
basic_science · Level V
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- Record sourced from PubMed, PMID 33145825.
- Also identified by DOI 10.1002/adma.202005315.
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Abstract
Emergent topological insulators (TIs) and their design are in high demand for manipulating and transmitting spin information toward ultralow-power-consumption spintronic applications. Here, distinct topological states with tailored spin properties can be achieved in a single reduced-dimensional TI-superlattice, (Bi<sub>2</sub> /Bi<sub>2</sub> Se<sub>3</sub> )-(Bi<sub>2</sub> /Bi<sub>2</sub> Se<sub>3</sub> )<sub>N</sub> or (□/Bi<sub>2</sub> Se<sub>3</sub> )-(Bi<sub>2</sub> /Bi<sub>2</sub> Se<sub>3</sub> )<sub>N</sub> (N is the repeating unit, □ represents an empty layer) by controlling the termination via molecular beam epitaxy. The Bi<sub>2</sub> -terminated superlattice exhibits a single Dirac cone with a spin momentum splitting ≈0.5 Å<sup>-1</sup> , producing a pronounced inverse Edelstein effect with a coherence length up to 1.26 nm. In contrast, the Bi<sub>2</sub> Se<sub>3</sub> -terminated superlattice is identified as a dual TI protected by coexisting time reversal and mirror symmetries, showing an unexpectedly long spin lifetime up to 1 ns. The work elucidates the key role of dimensionality and dual topological phases in selecting desired spin properties, suggesting a promise route for engineering topological superlattices for high-performance TI-spintronic devices.