Energy transport by neutral collective excitations at the quantum Hall edge

TL;DR

This study investigates neutral collective excitations at quantum Hall edges, revealing upstream energy transfer likely caused by neutral modes, using a novel experimental setup to distinguish charge and energy transport.

Contribution

It introduces a new sample design enabling independent measurement of charge and energy transport, and provides experimental evidence for neutral modes at quantum Hall edges.

Findings

Upstream energy transfer observed at filling factors 1 and 1/3.

Neutral collective mode identified as a candidate for energy transfer.

Novel experimental approach distinguishes charge and energy transport.

Abstract

We use the edge of the quantum Hall sample to study the possibility for counter-propagating neutral collective excitations. A novel sample design allows us to independently investigate charge and energy transport along the edge. We experimentally observe an upstream energy transfer with respect to the electron drift for the filling factors 1 and 1/3. Our analysis indicates that a neutral collective mode at the interaction-reconstructed edge is a proper candidate for the experimentally observed effect.