Robust electron pairing in the integer quantum hall effect regime.

H.K Choi,V Umansky,D Mahalu,A Rosenblatt,M Heiblum,I Sivan

doi:10.1038/ncomms8435

H.K Choi, V Umansky + Show 4 more

Open Access

https://doi.org/10.1038/ncomms8435

Copy DOI

Journal: Nature communications	Publication Date: Jun 22, 2015
Citations: 41	License type: cc-by

Affiliation: Weizmann Institute of Science

Abstract

Electron pairing is a rare phenomenon appearing only in a few unique physical systems; for example, superconductors and Kondo-correlated quantum dots. Here, we report on an unexpected electron pairing in the integer quantum Hall effect regime. The pairing takes place within an interfering edge channel in an electronic Fabry-Perot interferometer at a wide range of bulk filling factors, between 2 and 5. We report on three main observations: high-visibility Aharonov-Bohm conductance oscillations with magnetic flux periodicity equal to half the magnetic flux quantum; an interfering quasiparticle charge equal to twice the elementary electron charge as revealed by quantum shot noise measurements, and full dephasing of the pairs' interference by induced dephasing of the adjacent inner edge channel-a manifestation of inter-channel entanglement. Although this pairing phenomenon clearly results from inter-channel interaction, the exact mechanism that leads to electron-electron attraction within a single edge channel is not clear. We believe that substantial efforts are needed in order to clarify these intriguing and unexpected findings.

Highlights

Electron pairing is a rare phenomenon appearing only in a few unique physical systems; for example, superconductors and Kondo-correlated quantum dots
We address the Fabry–Perot interferometer (FPI) in the AB regime, which is formed by two quantum point contacts (QPCs) that serve as electronic beam splitters
The most outer edge channel was partitioned by the QPCs, whereas the impinging inner ones were fully reflected from the QPCs and, likely, the trapped ones circulated inside the FPI

Summary

Introduction

Electron pairing is a rare phenomenon appearing only in a few unique physical systems; for example, superconductors and Kondo-correlated quantum dots. We report on three main observations: high-visibility Aharonov–Bohm conductance oscillations with magnetic flux periodicity equal to half the magnetic flux quantum; an interfering quasiparticle charge equal to twice the elementary electron charge as revealed by quantum shot noise measurements, and full dephasing of the pairs’ interference by induced dephasing of the adjacent inner edge channel—a manifestation of inter-channel entanglement. This pairing phenomenon clearly results from inter-channel interaction, the exact mechanism that leads to electron– electron attraction within a single edge channel is not clear. The transmission through the interferometer is an oscillating function of the acquired AB phase in a single winding in the FPI: jtj21⁄4

Methods

Results

Conclusion