Does shot noise always provide the quasiparticle charge?

Abstract

The fractional charge of quasiparticles is a fundamental feature of quantum Hall effect (QHE) States. The charge has long been measured via shot-noise at moderate temperatures ($T$>30mK), with the Fano factor $F=e^{\ast }/e$ revealing the charge $e^{\ast }$ of the quasiparticles. However, at sufficiently low temperatures ($T\approx$10mK), we consistently find $F$ being equal to the bulk filling factor, ${\nu }_b$. Surprisingly, noise with $F={\nu }_b$ is also observed on intermediate conductance plateaus in the transmission of the quantum point contact (QPC), where shot noise is not expected. We attribute the unexpected Fano factor to upstream neutral modes, which proliferate at the lowest spinless Landau level. The universality of the Fano factor is also confirmed when the edge modes do not conform to the bulk. For this, the ubiquitous edge modes at the periphery of the sample are replaced by artificially constructed 'interface modes', propagating at the interface between two adjoined QHE states: the tested state and a different state. We present a new theoretical paradigm based on an interplay between charge and neutral modes, explaining the origin of the universal Fano factor.

43 pages, 4 main figures, supplementary material

References in corpus (14)

• Fractional Chern insulators in magic-angle twisted bilayer graphene
• Anyons and the quantum Hall effect - a pedagogical review
• Observation of neutral modes in the fractional quantum Hall regime
• Wavefunctionology: The Special Structure of Certain Fractional Quantum Hall Wavefunctions
• Thirty Years of Composite Fermions and Beyond
• Spin Gauge Fields: from Berry Phase to Topological Spin Transport and Hall Effects
• Melting of interference in the fractional quantum Hall effect: Appearance of neutral modes
• Direct evidence for Cooper pairing without a spectral gap in a disordered superconductor above $T_C$
• Conductance plateaus and shot noise in fractional quantum Hall point contacts
• Why a noninteracting model works for shot noise in fractional charge experiments
• Charge equilibration in integer and fractional quantum Hall edge channels in a generalized Hall-bar device
• Spin Mode-Switching at the Edge of a Quantum Hall System
• Emergence of Neutral Modes in Laughlin-like Fractional Quantum Hall Phases
• Edge Reconstruction and Emergent Neutral Modes in Integer and Fractional Quantum Hall Phases

Cited by in corpus (17)

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• Electron Pairing of Interfering Interface-Based Edge Modes
• Multiple Mechanisms for Emerging Conductance Plateaus in Fractional Quantum Hall States
• Molecular anyons in fractional quantum Hall effect
• Anomalous Aharonov-Bohm Interference in the Presence of Edge Reconstruction
• Different fractional charges from auto- and cross-correlation noise in quantum Hall states without upstream modes
• Transport Signatures of Fractional Quantum Hall Binding Transitions
• Experimentally Motivated Order of Length Scales Affect Shot Noise
• Probing anyon statistics on a single-edge loop in the fractional quantum Hall regime
• Non-Abelian phases from the condensation of Abelian anyons
• Photo-assisted shot noise probes multiple charge carriers in quantum Hall edges
• Tunable anyonic permeability across ${\mathbb{Z}}_2$ spin liquid junctions
• Shot noise signatures of candidate states for the fractional quantum Hall $\nu =12/5$ state
• Collapse of edge reconstruction in compressible Quantum Hall fluid within filling fraction range 2/3 to 1
• Elevated Hall Responses as Indicators of Edge Reconstruction