Evidence on the macroscopic length scale spin coherence for the edge currents in a narrow HgTe quantum well

Abstract

We experimentally investigate spin-polarized electron transport between two ferromagnetic contacts, placed at the edge of a two-dimensional electron system with band inversion. The system is realized in a narrow (8~nm) HgTe quantum well, the ferromagnetic side contacts are formed from a pre-magnetized permalloy film. In zero magnetic field, we find a significant edge current contribution to the transport between two ferromagnetic contacts. We experimentally demonstrate that this transport is sensitive to the mutual orientation of the magnetization directions of two 200~$\mu$m-spaced ferromagnetic leads. This is a direct experimental evidence on the spin-coherent edge transport over the macroscopic distances. Thus, the spin is extremely robust at the edge of a two-dimensional electron system with band inversion, confirming the helical spin-resolved nature of edge currents.

arXiv admin note: text overlap with arXiv:1410.0585

References in corpus (6)

• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Nonlocal edge state transport in the quantum spin Hall state
• Helical edge states coupled to a spin bath: Current-induced magnetization
• Detection of current-induced spins by ferromagnetic contacts
• Transition from insulating to metallic phase induced by in-plane magnetic field in HgTe quantum wells
• Current-induced magnetization dynamics at the edge of a two-dimensional electron system with strong spin-orbit coupling

Cited by in corpus (14)

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• High-frequency nonlinear transport and photogalvanic effects in two-dimensional topological insulators
• Helical edge transport in the presence of a magnetic impurity
• Helical edge transport in the presence of a magnetic impurity: the role of local anisotropy
• Coherent spin transport through helical edge states of topological insulator
• Optical properties of helical edge channels in zinc-blende-type topological insulators: Selection rules, circular and linear dichroism, circular and linear photocurrents
• Finite frequency backscattering current noise at a helical edge
• Analytical and Numerical study of the out-of-equilibrium current through a helical edge coupled to a magnetic impurity
• Tunneling Aharonov-Bohm interferometer on helical edge states
• Spin and charge transport through helical Aharonov-Bohm interferometer with strong magnetic impurity
• Tunable helical crystals
• Formation of bound states from the edge states of 2D topological insulator by macroscopic magnetic barriers
• Effective Hamiltonian of topologically protected qubit in a helical crystal