Probing fractional topological insulators with magnetic edge perturbations

TL;DR

This paper explores methods to detect fractional topological insulators by analyzing how magnetic edge perturbations affect edge modes, revealing robustness and phase transition signatures useful for experimental identification.

Contribution

It introduces detection protocols using transport measurements to identify FTIs and characterizes their universal properties through magnetic perturbations.

Findings

Edge modes are robust against moderate magnetic backscattering.

Magnetic perturbations induce phase transitions signaling the FTI phase.

Protocols enable extraction of universal phase parameters from conductance data.

Abstract

We discuss detection strategies for fractional topological insulators (FTIs) realizing time-reversal invariant analogues of fractional quantum Hall systems in the Laughlin universality class. Focusing on transport measurements, we study the effect of magnetic perturbations on the edge modes. We find that the modes show unexpected robustness against magnetic backscattering for moderate couplings and edge interactions, allowing for various phase transitions signaling the FTI phase. We also describe protocols for extracting the universal integer m characterizing the phase and the edge interaction parameter from the conductance of setups with magnets and a quantum point contact.