# Universal quantized thermal conductance in graphene

## TL;DR

This study demonstrates universal quantized thermal conductance in graphene quantum Hall states, indicating the absence of edge reconstruction and highlighting graphene's suitability for studying exotic quasiparticles.

## Contribution

The paper provides the first measurement of quantized thermal conductance in graphene, showing high accuracy and suggesting no edge reconstruction in fractional quantum Hall states.

## Key findings

- Quantized thermal conductance observed within 5% accuracy for multiple filling factors.
- Results indicate the absence of edge reconstruction in graphene fractional quantum Hall states.
- Graphene's edge states are suitable for interference experiments with exotic quasiparticles.

## Abstract

The universal quantization of thermal conductance provides information on the topological order of a state beyond electrical conductance. Such measurements have become possible only recently, and have discovered, in particular, that the value of the observed thermal conductance of the 5/2 state is not consistent with either the Pfaffian or the anti-Pfaffian model, motivating several theoretical articles. The analysis of the experiments has been made complicated by the presence of counter-propagating edge channels arising from edge reconstruction, an inevitable consequence of separating the dopant layer from the GaAs quantum well. In particular, it has been found that the universal quantization requires thermalization of downstream and upstream edge channels. Here we measure the thermal conductance in hexagonal boron nitride encapsulated graphene devices of sizes much smaller than the thermal relaxation length of the edge states. We find the quantization of thermal conductance within 5% accuracy for {\nu} = 1, 4/3, 2 and 6 plateaus and our results strongly suggest the absence of edge reconstruction for fractional quantum Hall in graphene, making it uniquely suitable for interference phenomena exploiting paths of exotic quasiparticles along the edge.