title: Quantum spin Hall insulators in centrosymmetric thin films composed from topologically trivial BiTeI trilayers.
abstract: The quantum spin Hall insulators predicted ten years ago and now experimentally observed are instrumental for a break- through in nanoelectronics due to non-dissipative spin-polarized electron transport through their edges. For this transport to persist at normal conditions, the insulators should possess a sufficiently large band gap in a stable topological phase. Here, we theoretically show that quantum spin Hall insulators can be realized in ultra-thin films constructed from a trivial band insulator with strong spin-orbit coupling. The thinnest film with an inverted gap large enough for practical applications is a centrosymmetric sextuple layer built out of two inversely stacked non-centrosymmetric BiTeI trilayers. This nontrivial sextuple layer turns out to be the structure element of an artificially designed strong three-dimensional topological insulator Bi2Te2I2. We reveal general principles of how a topological insulator can be composed from the structure elements of the BiTeX family (X = I, Br, Cl), which opens new perspectives towards engineering of topological phases.
authors.affiliation: Centro de Física de Materiales CFM - MPC and Centro Mixto CSIC-UPV/EHU, 20018 San Sebastián/Donostia, Spain.|Tomsk State University, 634050, Tomsk, Russia.|Saint Petersburg State University, 198504, Saint Petersburg, Russia.
authors.forename: I A
authors.initials: IA
authors.lastname: Nechaev
authors.affiliation: Tomsk State University, 634050, Tomsk, Russia.|Saint Petersburg State University, 198504, Saint Petersburg, Russia.|Institute of Strength Physics and Materials Science, 634055, Tomsk, Russia.|Donostia International Physics Center, 20018 San Sebastián/Donostia, Spain.
authors.forename: S V
authors.initials: SV
authors.lastname: Eremeev
authors.affiliation: Donostia International Physics Center, 20018 San Sebastián/Donostia, Spain.|Departamento de Física de Materiales UPV/EHU, Facultad de Ciencias Químicas, UPV/EHU, Apdo. 1072, 20080 San Sebastián/Donostia, Spain.|IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain.
authors.forename: E E
authors.initials: EE
authors.lastname: Krasovskii
authors.affiliation: Donostia International Physics Center, 20018 San Sebastián/Donostia, Spain.|Departamento de Física de Materiales UPV/EHU, Facultad de Ciencias Químicas, UPV/EHU, Apdo. 1072, 20080 San Sebastián/Donostia, Spain.
authors.forename: P M
authors.initials: PM
authors.lastname: Echenique
authors.affiliation: Centro de Física de Materiales CFM - MPC and Centro Mixto CSIC-UPV/EHU, 20018 San Sebastián/Donostia, Spain.|Tomsk State University, 634050, Tomsk, Russia.|Saint Petersburg State University, 198504, Saint Petersburg, Russia.|Donostia International Physics Center, 20018 San Sebastián/Donostia, Spain.|Departamento de Física de Materiales UPV/EHU, Facultad de Ciencias Químicas, UPV/EHU, Apdo. 1072, 20080 San Sebastián/Donostia, Spain.
authors.forename: E V
authors.initials: EV
authors.lastname: Chulkov