Transport phenomena in helical edge states interferometers. A Green's function approach

Abstract

We analyze the current and the shot-noise of an electron interferometer made of the helical edge states of a two-dimensional topological insulator within the framework of non-equilibrium Green's functions formalism. We study in detail setups with a single and with two quantum point contacts inducing scattering between the different edge states. We consider processes preserving the spin as well as the effect of spin-flip scattering. In the case of a single quantum point contact, a simple test based on the shot-noise measurement is proposed to quantify the strength of the spin-flip scattering. In the case of two single point contacts with the additional ingredient of gate voltages applied within a finite-size region at the top and bottom edges of the sample, we identify two type of interference processes in the behavior of the currents and the noise. One of such processes is analogous to that taking place in a Fabry-Pérot interferometer, while the second one corresponds to a configuration similar to a Mach-Zehnder interferometer. In the helical interferometer these two processes compete.

15 pages, 13 figures

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Cited by in corpus (18)

• Disorder enabled band structure engineering of a topological insulator surface
• Electronic Hong-Ou-Mandel interferometry in two-dimensional topological insulators
• Nonlinear spin-thermoelectric transport in two-dimensional topological insulators
• Tunnel junction of helical edge states: Determining and controlling spin-preserving and spin-flipping processes through transconductance
• Shot noise in the edge states of 2D topological insulators
• Optimal thermoelectricity with quantum spin-Hall edge states
• Phase-tunable thermal rectification in the topological SQUIPT
• Helical spin thermoelectrics controlled by a side-coupled magnetic quantum dot in the quantum spin Hall state
• Electronic quantum optics beyond the integer quantum Hall effect
• Noise and current correlations in tunnel junctions of Quantum Spin Hall edge states
• Effects of disorder on electron tunneling through helical edge states
• Connection topology of step edge state bands at the surface of a three dimensional topological insulator
• Noise in the helical edge channel anisotropically coupled to a local spin
• Emission of entangled Kramers pairs from a helical mesoscopic capacitor
• Anisotropic Fabry-Pérot resonant states confined within nano-steps on the topological insulator surface
• Fabry-Pérot interferometry with gate-tunable 3D topological insulator nanowires
• Transport in quantum spin Hall edges in contact to a quantum dot
• Tunneling between helical Majorana modes and helical Luttinger liquids