Disorder enabled band structure engineering of a topological insulator surface.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28155858.
- Also identified by DOI 10.1038/ncomms14081 and PMC identifier 5296772.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Three-dimensional topological insulators are bulk insulators with Z<sub>2</sub> topological electronic order that gives rise to conducting light-like surface states. These surface electrons are exceptionally resistant to localization by non-magnetic disorder, and have been adopted as the basis for a wide range of proposals to achieve new quasiparticle species and device functionality. Recent studies have yielded a surprise by showing that in spite of resisting localization, topological insulator surface electrons can be reshaped by defects into distinctive resonance states. Here we use numerical simulations and scanning tunnelling microscopy data to show that these resonance states have significance well beyond the localized regime usually associated with impurity bands. At native densities in the model Bi<sub>2</sub>X<sub>3</sub> (X=Bi, Te) compounds, defect resonance states are predicted to generate a new quantum basis for an emergent electron gas that supports diffusive electrical transport.