Exploiting the close-to-Dirac point shift of Fermi level in Sb2Te3/Bi2Te3 topological insulator heterostructure for spin-charge conversion

Abstract

Properly tuning the Fermi level position in topological insulators is of vital importance to tailor their spin-polarized electronic transport and to improve the efficiency of any functional device based on them. Here we report the full in situ Metal Organic Chemical Vapor Deposition (MOCVD) and study of a highly crystalline Bi2Te3/Sb2Te3 topological insulator heterostructure on top of large area (4'') Si(111) substrates. The bottom Sb2Te3 layer serves as an ideal seed layer for the growth of highly crystalline Bi2Te3 on top, also inducing a remarkable shift of the Fermi level to place it very close to the Dirac point, as visualized by angle-resolved photoemission spectroscopy. In order to exploit such ideal topologically-protected surface states, we fabricate the simple spin-charge converter Si(111)/Sb2Te3/Bi2Te3/Au/Co/Au and spin-charge conversion (SCC) is probed by spin pumping ferromagnetic resonance. A large SCC is measured at room temperature, which is interpreted within the inverse Edelstein effect (IEE), thus resulting in a conversion efficiency lambda_IEE of 0.44 nm. Our results demonstrate the successful tuning of the surface Fermi level of Bi2Te3 when grown on top of Sb2Te3 with a full in situ MOCVD process, which is highly interesting in view of its future technology transfer.

Main text: 19 pages, 6 figures. Supplementary information are also included in the file with additional 4 pages

References in corpus (5)

• Emergent Phenomena Induced by Spin-Orbit Coupling at Surfaces and Interfaces
• Observation of inverse spin Hall effect in bismuth selenide
• Dirac-Surface-State-Dominated Spin to Charge Current Conversion in the Topological Insulator $(B{i}_{0.22}S{b}_{0.78}{)}_{2}T{e}_3$ Films at Room Temperature
• Characterizing the Structure of Topological Insulator Thin Films
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Cited by in corpus (5)

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• Large-Scale Epitaxial Integration of Single-Crystalline BiSb Topological Insulator on GaAs (111)A
• Gate-Tunable Spin-to-Charge Conversion in Topological Insulator-Magnetic Insulator Heterostructures at Room Temperature
• Probing the Spin-Momentum Locking in Rashba Surfaces via Spin Current
• Terahertz time-domain signatures of the inverse Edelstein effect in topological-insulator|ferromagnet heterostructures