Nonequilibrium noise correlations in a point contact of helical edge states

Yu Wen Lee*, Yu Li Lee, Chung-Hou Chung

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


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.

Original languageEnglish
Article number235121
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number23
StatePublished - 17 Dec 2012


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