Sub- to Super-Poissonian crossover of current noise in helical edge states coupled to a spin impurity in a magnetic field

authored by: Benedikt Probst, Pauli Virtanen, Patrik Recher
Abstract: Edge states of two-dimensional topological insulators are helical and single-particle backscattering is prohibited by time-reversal symmetry. In this work, we show that an isotropic exchange coupling of helical edge states (HES) to a spin 1/2 impurity subjected to a magnetic field results in characteristic backscattering current noise (BCN) as a function of bias voltage and tilt angle between the direction of the magnetic field and the quantization axis of the HES. In particular, we find transitions from sub-Poissonian (antibunching) to super-Poissonian (bunching) behavior as a direct consequence of the helicity of the edge state electrons. We use the method of full counting statistics within a master equation approach treating the exchange coupling between the spin-1/2 impurity and the HES perturbatively. We express the BCN via coincidence correlation functions of scattering processes between the HES which gives a precise interpretation of the Fano factor in terms of bunching and antibunching behavior of electron jump events. We also investigate the effect of electron-electron interactions in the HES in terms of the Tomonaga-Luttinger liquid theory.
External Organisation(s): Technische Universität Braunschweig
University of Jyvaskyla
Laboratory for Emerging Nanometrology Braunschweig (LENA)
Type: Article
Journal: Physical Review B
Volume: 106
ISSN: 2469-9950
Publication date: 04.08.2022
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Condensed Matter Physics
Electronic version(s): http://arxiv.org/abs/2108.00233v1 (Access: Open)
https://doi.org/10.1103/PhysRevB.106.085406 (Access: Closed)

BibTeX

@article{18316e6147dd4e21b67c559da25bf789,
title = "Sub- to Super-Poissonian crossover of current noise in helical edge states coupled to a spin impurity in a magnetic field",
abstract = " Edge states of two-dimensional topological insulators are helical and single-particle backscattering is prohibited by time-reversal symmetry. In this work, we show that an isotropic exchange coupling of helical edge states (HES) to a spin 1/2 impurity subjected to a magnetic field results in characteristic backscattering current noise (BCN) as a function of bias voltage and tilt angle between the direction of the magnetic field and the quantization axis of the HES. In particular, we find transitions from sub-Poissonian (antibunching) to super-Poissonian (bunching) behavior as a direct consequence of the helicity of the edge state electrons. We use the method of full counting statistics within a master equation approach treating the exchange coupling between the spin-1/2 impurity and the HES perturbatively. We express the BCN via coincidence correlation functions of scattering processes between the HES which gives a precise interpretation of the Fano factor in terms of bunching and antibunching behavior of electron jump events. We also investigate the effect of electron-electron interactions in the HES in terms of the Tomonaga-Luttinger liquid theory. ",
keywords = "cond-mat.mes-hall",
author = "Benedikt Probst and Pauli Virtanen and Patrik Recher",
note = "Funding information: P.V. acknowledges funding from EU's Horizon 2020 research, from the innovation program under Grant Agreement No. 800923 (SUPERTED) and from Academy of Finland Project No. 317118. P.R. acknowledges financial support by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) within the framework of Germany's Excellence Strategy–EXC-2123 QuantumFrontiers–390837967.",
year = "2022",
month = aug,
day = "4",
doi = "10.1103/PhysRevB.106.085406",
language = "English",
volume = "106",
journal = "Physical Review B",
issn = "2469-9950",
publisher = "American Institute of Physics",
number = "8",
}