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Observation of ballistic upstream modes at fractional quantum Hall edges of graphene

Kumar, Ravi; Srivastav, Saurabh Kumar; Spånslätt, Christian; Watanabe, K.; Taniguchi, T.; Gefen, Yuval; Mirlin, Alexander D.; Das, Anindya

Abstract (englisch):

The presence of “upstream”modes, moving against the direction of charge current flow in the fractional quantum Hall (FQH) phases, is critical for the emergence of renormalized modes with exotic quantum statistics. Detection of excess noise at the edge is a smoking gun for the presence of upstream modes. Here, we report noise measurements at the edges of FQH states realized in dual graphite-gated bilayer graphene devices. A noiseless dc current is injected at one of the edge contacts, and the noise generated at contacts at length, L =4 μm
and 10 μm away along the upstream direction is studied. For integer and particle-like FQH states, no detectable noise is measured. By contrast, for “hole-conjugate”FQH states, we
detect a strong noise proportional to the injected current, unambiguously proving the existence of upstream modes. The noise magnitude remains independent of length, which
matches our theoretical analysis demonstrating the ballistic nature of upstream energy transport, quite distinct from the diffusive propagation reported earlier in GaAs-based systems.


Verlagsausgabe §
DOI: 10.5445/IR/1000142146
Veröffentlicht am 20.01.2022
Originalveröffentlichung
DOI: 10.1038/s41467-021-27805-4
Scopus
Zitationen: 24
Web of Science
Zitationen: 22
Dimensions
Zitationen: 27
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für QuantenMaterialien und Technologien (IQMT)
Institut für Theorie der Kondensierten Materie (TKM)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 12.2022
Sprache Englisch
Identifikator ISSN: 2041-1723
KITopen-ID: 1000142146
HGF-Programm 47.12.01 (POF IV, LK 01) Advanced Solid-State Qubits and Qubit Systems
Erschienen in Nature Communications
Verlag Nature Research
Band 13
Heft 1
Seiten Art.-Nr.: 213
Vorab online veröffentlicht am 11.01.2022
Nachgewiesen in Scopus
Web of Science
Dimensions
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