# Nuclear-spin-induced localization of the edge states in two-dimensional topological insulators

## TL;DR

This paper explores how nuclear spins cause backscattering in two-dimensional topological insulator edge states, leading to increased resistance and potential conductance shutdown at low temperatures.

## Contribution

It identifies two distinct nuclear-spin-induced backscattering mechanisms and analyzes their temperature and interaction dependencies in 2DTIs.

## Key findings

- Nuclear spins enable backscattering, breaking time reversal symmetry.
- Resistance increases with edge length, decreasing temperature, and stronger electron interactions.
- Nuclear spins can suppress edge conductance at zero temperature.

## Abstract

We investigate the influence of nuclear spins on the resistance of helical edge states of two-dimensional topological insulators (2DTIs). Via the hyperfine interaction, nuclear spins allow electron backscattering, otherwise forbidden by time reversal symmetry. We identify two backscattering mechanisms, depending on whether the nuclear spins are ordered or not. Their temperature dependence is distinct but both give resistance, which increases with the edge length, decreasing temperature, and increasing strength of the electron-electron interaction. Overall, we find that the nuclear spins will typically shut down the conductance of the 2DTI edges at zero temperature.