# Dynamical separation of bulk and edge transport in HgTe-based 2D topological insulators

## TL;DR

This paper demonstrates that microwave spectroscopy can dynamically distinguish between fast-moving edge states and slow bulk carriers in HgTe-based 2D topological insulators, enabling selective edge state analysis.

## Contribution

It introduces a method to separate edge and bulk transport dynamically, revealing that edge states can be addressed selectively over short timescales despite their high density.

## Key findings

- Edge states exhibit high mobility compared to bulk carriers.
- Charge relaxation occurs on short timescales, allowing selective edge state access.
- Bulk carriers are significantly slowed down in the energy gap.

## Abstract

Topological effects in edge states are clearly visible on short lengths only, thus largely impeding their studies. On larger distances, one may be able to dynamically enhance topological signatures by exploiting the high mobility of edge states with respect to bulk carriers. Our work on microwave spectroscopy highlights the responses of the edges which host very mobile carriers, while bulk carriers are drastically slowed down in the gap. Though the edges are denser than expected, we establish that charge relaxation occurs on short timescales, and suggests that edge states can be addressed selectively on timescales over which bulk carriers are frozen.