Noninvasive Probe of Charge Fractionalization in Quantum Spin-Hall Insulators

TL;DR

This paper proposes two topological insulator devices designed to noninvasively detect charge fractionalization and velocities in quantum spin-Hall insulators, addressing previous measurement challenges.

Contribution

It introduces novel device designs that enable direct, noninvasive observation of fractional charges and their dynamics in topological insulators.

Findings

Devices allow direct detection of fractional charges.

Method reduces backscattering effects.

Enables measurement of charge velocities.

Abstract

When an electron with well-defined momentum tunnels into a nonchiral Luttinger liquid, it breaks up into two separate wave packets that carry fractional charges and move in opposite directions. A direct observation of this phenomenon has proven elusive, mainly due to single-particle and plasmon backscattering caused by measurement probes. This paper theoretically introduces two topological insulator devices that are naturally suited for detecting fractional charges and their velocities directly and in a noninvasive fashion.