Thin-film hybrid structures of topological insulators with superconductors and ferromagnets: experiment and theory

• Applicants: Professor Dr. Thomas Dahm; Professor Dr. Günter Reiss
• Subject Area: Experimental Condensed Matter Physics ; Theoretical Condensed Matter Physics
• Term: from 2016 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 314727505

In a joint experimental and theoretical effort we investigate thin-film hybrid structures of topological insulators with ferromagnets or superconductors. We aim to develop techniques to detect and access the topological surface states by tunnelling spectroscopy and proximity effects for device applications in spintronics. On the experimental side we plan to grow insulators, ferromagnets, or superconductors on Bi2Se3, Bi2Te3 and compensated Bi-(Te,Se) thin films. We also plan to investigate new topological materials within the hexaborides and Weyl semimetals. Simple devices are proposed to detect and exploit the spin-orbit coupled nature of the topological surface states. The devices will be characterized by spin-dependent tunnelling spectroscopy, Andreev reflection, and Spin-Hall spectroscopy. The experimental studies will be complemented by theoretical investigations of the devices in order to detect the topological surface states, characterize their properties, and control the spin current flow. The theoretical studies will employ exact diagonalization of tight-binding models for hybrid structures of topological insulators, ferromagnets, and superconductors.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1666: Topological Insulators: Materials - Fundamental Properties - Devices
• Co-Investigators: Dr. Karsten Rott; Dr. Jan Michael Schmalhorst