Finite frequency backscattering current noise at a helical edge
Abstract
Magnetic impurities with sufficient anisotropy could account for the observed strong deviation of the edge conductance of 2D topological insulators from the anticipated quantized value. In this work we consider such a helical edge coupled to dilute impurities with an arbitrary spin S and a general form of the exchange matrix. We calculate the backscattering current noise at finite frequencies as a function of the temperature and applied voltage bias. We find that, in addition to the Lorentzian resonance at zero frequency, the backscattering current noise features Fanotype resonances at nonzero frequencies. The widths of the resonances are controlled by the spectrum of corresponding Korringa rates. At a fixed frequency the backscattering current noise has nonmonotonic behavior as a function of the bias voltage.
 Publication:

Physical Review B
 Pub Date:
 September 2020
 DOI:
 10.1103/PhysRevB.102.125309
 arXiv:
 arXiv:2007.08245
 Bibcode:
 2020PhRvB.102l5309P
 Keywords:

 Condensed Matter  Mesoscale and Nanoscale Physics;
 Condensed Matter  Strongly Correlated Electrons
 EPrint:
 12 LaTeX pages, 4 figures