A1 Journal article (refereed)
Sub- to super-Poissonian crossover of current noise in helical edge states coupled to a spin impurity in a magnetic field (2022)

Probst, B., Virtanen, P., & Recher, P. (2022). Sub- to super-Poissonian crossover of current noise in helical edge states coupled to a spin impurity in a magnetic field. Physical Review B, 106(8), Article 085406. https://doi.org/10.1103/PhysRevB.106.085406

JYU authors or editors

Virtanen, Pauli

Publication details

All authors or editors: Probst, Benedikt; Virtanen, Pauli; Recher, Patrik

Journal or series: Physical Review B

ISSN: 2469-9950

eISSN: 2469-9969

Publication year: 2022

Publication date: 04/08/2022

Volume: 106

Issue number: 8

Article number: 085406

Publisher: American Physical Society (APS)

Publication country: United States

Publication language: English

DOI: https://doi.org/10.1103/PhysRevB.106.085406

Publication open access: Not open

Publication channel open access:

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/82967

Web address of parallel published publication (pre-print): https://arxiv.org/abs/2108.00233

Abstract

Edge states of two-dimensional topological insulators are helical and single-particle backscattering is prohibited by time-reversal symmetry. In this paper, 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: solid-state physics; electric conductivity; spin (quantum mechanics); magnetic fields

Fields of science: