Nonequilibrium noise correlations in a point contact of helical edge states

Abstract

We investigate theoretically the nonequilibrium finite-frequency current noise in a four-terminal quantum point contact of interacting helical edge states at a finite bias voltage. Special focus is put on the effects of the single-particle and two-particle scattering between the two helical edge states on the fractional charge quasiparticle excitations shown in the nonequilibrium current noise spectra. Via the Keldysh perturbative approach, we find that the effects of the single-particle and the two-particle scattering processes on the current noise depend sensitively on the Luttinger liquid parameter. Moreover, the Fano factors for the auto- and cross correlations of the currents in the terminals are distinct from the ones for tunneling between the chiral edge states in the quantum Hall liquid. The current noise spectra in the single-particle-scattering-dominated and the two-particle-scattering-dominated regime are shown. Experimental implications of our results on the transport through the helical edges in two-dimensional topological insulators are discussed.

10 pages, 8 figures

References in corpus (6)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Nonlocal edge state transport in the quantum spin Hall state
• The Helical Liquid and the Edge of Quantum Spin Hall Systems
• Corner Junction as a Probe of Helical Edge States
• Finite frequency noise in a quantum point contact between helical edge states

Cited by in corpus (13)

• Helical Liquids in Semiconductors
• Tunnel junction of helical edge states: Determining and controlling spin-preserving and spin-flipping processes through transconductance
• Z2 peak of noise correlations in a quantum spin Hall insulator
• Current noise from a magnetic moment in a helical edge
• Spin-orbit interactions in a helical Luttinger liquid with a Kondo impurity
• Noise and current correlations in tunnel junctions of Quantum Spin Hall edge states
• Probing helicity and the topological origins of helicity via non-local Hanbury-Brown and Twiss correlations
• Point contacts and localization in generic helical liquids
• Chirality and Current-Current Correlation in Fractional Quantum Hall Systems
• Effects of disorder on electron tunneling through helical edge states
• Interaction effects in non-equilibrium transport properties of a four-terminal topological corner junction
• Nonequilibrium transport of helical Luttinger liquids through a quantum dot
• Current enhancement through a time dependent constriction in fractional topological insulators