Strongly coupled edge states in a graphene quantum Hall interferometer

Fuente: arXiv
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Main Authors: Werkmeister, Thomas, Ehrets, James R., Ronen, Yuval, Wesson, Marie E., Najafabadi, Danial, Wei, Zezhu, Watanabe, Kenji, Taniguchi, Takashi, Feldman, D. E., Halperin, Bertrand I., Yacoby, Amir, Kim, Philip
Format: Preprint
Published: 2023
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author Werkmeister, Thomas
Ehrets, James R.
Ronen, Yuval
Wesson, Marie E.
Najafabadi, Danial
Wei, Zezhu
Watanabe, Kenji
Taniguchi, Takashi
Feldman, D. E.
Halperin, Bertrand I.
Yacoby, Amir
Kim, Philip
author_facet Werkmeister, Thomas
Ehrets, James R.
Ronen, Yuval
Wesson, Marie E.
Najafabadi, Danial
Wei, Zezhu
Watanabe, Kenji
Taniguchi, Takashi
Feldman, D. E.
Halperin, Bertrand I.
Yacoby, Amir
Kim, Philip
contents Electronic interferometers using the chiral, one-dimensional (1D) edge channels of the quantum Hall effect (QHE) can demonstrate a wealth of fundamental phenomena. The recent observation of phase jumps in a Fabry-Pérot (FP) interferometer revealed anyonic quasiparticle exchange statistics in the fractional QHE. When multiple integer edge channels are involved, FP interferometers have exhibited anomalous Aharonov-Bohm (AB) interference frequency doubling, suggesting putative pairing of electrons into 2e quasiparticles. Here, we use a highly tunable graphene-based QHE FP interferometer to observe the connection between interference phase jumps and AB frequency doubling, unveiling how strong repulsive interaction between edge channels leads to the apparent pairing phenomena. By tuning electron density in-situ from filling factor ν<2 to ν>7, we tune the interaction strength and observe periodic interference phase jumps leading to AB frequency doubling. Our observations demonstrate that the combination of repulsive interaction between the spin-split ν=2 edge channels and charge quantization is sufficient to explain the frequency doubling, through a near-perfect charge screening between the localized and extended edge channels. Our results show that interferometers are sensitive probes of microscopic interactions and enable future experiments studying correlated electrons in 1D channels using our highly tunable platform.
format Preprint
id arxiv_https___arxiv_org_abs_2312_03150
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Strongly coupled edge states in a graphene quantum Hall interferometer
Werkmeister, Thomas
Ehrets, James R.
Ronen, Yuval
Wesson, Marie E.
Najafabadi, Danial
Wei, Zezhu
Watanabe, Kenji
Taniguchi, Takashi
Feldman, D. E.
Halperin, Bertrand I.
Yacoby, Amir
Kim, Philip
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
Electronic interferometers using the chiral, one-dimensional (1D) edge channels of the quantum Hall effect (QHE) can demonstrate a wealth of fundamental phenomena. The recent observation of phase jumps in a Fabry-Pérot (FP) interferometer revealed anyonic quasiparticle exchange statistics in the fractional QHE. When multiple integer edge channels are involved, FP interferometers have exhibited anomalous Aharonov-Bohm (AB) interference frequency doubling, suggesting putative pairing of electrons into 2e quasiparticles. Here, we use a highly tunable graphene-based QHE FP interferometer to observe the connection between interference phase jumps and AB frequency doubling, unveiling how strong repulsive interaction between edge channels leads to the apparent pairing phenomena. By tuning electron density in-situ from filling factor ν<2 to ν>7, we tune the interaction strength and observe periodic interference phase jumps leading to AB frequency doubling. Our observations demonstrate that the combination of repulsive interaction between the spin-split ν=2 edge channels and charge quantization is sufficient to explain the frequency doubling, through a near-perfect charge screening between the localized and extended edge channels. Our results show that interferometers are sensitive probes of microscopic interactions and enable future experiments studying correlated electrons in 1D channels using our highly tunable platform.
title Strongly coupled edge states in a graphene quantum Hall interferometer
topic Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
url https://arxiv.org/abs/2312.03150