English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We investigate the lattice and electronic structures of the bulk and surfaceof the prototypical layered topological insulators Bi$_2$Se$_3$ andBi$_2$Te$_3$ using ab initio density functional methods, and systematicallycompare the results of different methods of including van der Waals (vdW)interactions. We show that the methods utilizing semi-empirical energycorrections yield accurate descriptions of these materials, with the mostprecise results obtained by properly accounting for the long-range tail of thevdW interactions. The bulk lattice constants, distances between quintuplelayers and the Dirac velocity of the topological surface states (TSS) are allin excellent agreement with experiment. In Bi$_2$Te$_3$, hexagonal warping ofthe energy dispersion leads to complex spin textures of the TSS at moderateenergies, while in Bi$_2$Se$_3$ these states remain almost perfectly helicalaway from the Dirac point, showing appreciable signs of hexagonal warping atmuch higher energies, above the minimum of the bulk conduction band. Ourresults establish a framework for unified and systematic self-consistent firstprinciples calculations of topological insulators in bulk, slab and interfacegeometries, and provides the necessary first step towards ab initio modeling oftopological heterostructures.

Importance of van der Waals interactions for ab initio studies of topological insulators