Noiseless manipulation of helical edge state transport by a quantum magnet

Abstract

The current through a helical edge state of a quantum-spin-Hall insulator may be fully transmitted through a magnetically gapped region due to a combination of spin-transfer torque and spin pumping [Meng {\em et al.}, Phys. Rev. B {\bf 90}, 205403 (2014)]. Using a scattering approach, we here argue that in such a system the current is effectively carried by electrons with energies below the magnet-induced gap and well below the Fermi energy. This has striking consequences, such as the absence of shot noise, an exponential suppression of thermal noise, and an obstruction of thermal transport. For two helical edges covered by the same quantum magnet, the device can act as robust noiseless current splitter.

5 pages, 3 figures

References in corpus (7)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Kondo effect in the helical edge liquid of the quantum spin Hall state
• Conductance of a helical edge liquid coupled to a magnetic impurity
• Microwave-driven ferromagnet--topological-insulator heterostructures: The prospect for giant spin battery effect and quantized charge pump devices
• Nanomagnet coupled to quantum spin Hall edge: An adiabatic quantum motor
• Transport in helical Luttinger Liquid with Kondo impurities

Cited by in corpus (14)

• ${\mathbb{Z}}_4$ Parafermions in an interacting quantum spin Hall Josephson junction coupled to an impurity spin
• Optimal thermoelectricity with quantum spin-Hall edge states
• Helical spin thermoelectrics controlled by a side-coupled magnetic quantum dot in the quantum spin Hall state
• Thermodynamics and steady state of quantum motors and pumps far from equilibrium
• An interacting adiabatic quantum motor
• Signatures of Jackiw-Rebbi resonance in the thermal conductance of topological Josephson junctions with magnetic islands
• Nonequilibrium current-induced forces caused by quantum localization: Anderson Adiabatic Quantum Motors
• Detailed study of nonlinear cooling with two-terminal configurations of topological edge states
• Current-induced switching of magnetic molecules on topological insulator surfaces
• Interference effects induced by a precessing easy-plane magnet coupled to a helical edge state
• Quantum transport phenomena induced by time-dependent fields
• Enhanced lifetimes of spin chains coupled to chiral edge states
• Electrically-detected single-spin resonance with Quantum Spin Hall edge states
• Finite-frequency admittance and noise of a helical edge coupled to a magnet