Self-organized topological insulator heterostructures via eutectic solidification of Bi2Te3-Te

Abstract

Topological insulators (TI) are generating increasing interest as a new state of matter and due to the potential use of topologically- protected gapless surface states in spintronic devices and quantum computing. However, challenges such as high sensitivity to the atmosphere, the low surface-to-volume ratio, and the need for various material junctions currently limit their application. Here, a novel, natural and simple approach to the fabrication of volumetric TI heterostructures that can overcome these core challenges is presented, using the example of a Bi2Te3-Te eutectic composite. The proposed method based on directional solidification of eutectic composites, enables the formation of ensembles of parallel TI-other material heterojunctions through a self-organization process. It also offers control over the heterostructures’ dimensions/refinement. Electron microscopy techniques show that the heterostructure exhibits a lamellar/layered microstructure with atomically smooth Bi2Te3ǀǀTe interfaces. Angle-resolved photoelectron spectroscopy experiments confirm the existence of metallic surface states, while Kelvin probe force microscopy depicts the formed p-n junctions. The new degrees of freedom offered here, such as control of heterojunction chemical composition, packing density, and available fabrication techniques, may facilitate large-scale customized printing of topological devices.

Keywords

• Topological insulators
• Heterostructures
• Eutectics
• Self-organization
• Bi2Te3
• Micro-pulling down method