Observation of edge and bulk states in a three-site Kitaev chain

Fuente: arXiv
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Main Authors: Haaf, Sebastiaan L. D. ten, Zhang, Yining, Wang, Qingzhen, Bordin, Alberto, Liu, Chun-Xiao, Kulesh, Ivan, Sietses, Vincent P. M., Prosko, Christian G., Xiao, Di, Thomas, Candice, Manfra, Michael J., Wimmer, Michael, Goswami, Srijit
Format: Preprint
Published: 2024
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author Haaf, Sebastiaan L. D. ten
Zhang, Yining
Wang, Qingzhen
Bordin, Alberto
Liu, Chun-Xiao
Kulesh, Ivan
Sietses, Vincent P. M.
Prosko, Christian G.
Xiao, Di
Thomas, Candice
Manfra, Michael J.
Wimmer, Michael
Goswami, Srijit
author_facet Haaf, Sebastiaan L. D. ten
Zhang, Yining
Wang, Qingzhen
Bordin, Alberto
Liu, Chun-Xiao
Kulesh, Ivan
Sietses, Vincent P. M.
Prosko, Christian G.
Xiao, Di
Thomas, Candice
Manfra, Michael J.
Wimmer, Michael
Goswami, Srijit
contents A chain of quantum dots (QDs) in semiconductor-superconductor hybrid systems can form an artificial Kitaev chain hosting Majorana bound states (MBSs). These zero-energy states are expected to be localised on the edges of the chain, at the outermost QDs. The remaining QDs, comprising the bulk, are predicted to host an excitation gap that protects the MBSs at the edges from local on-site perturbations. Here we demonstrate this connection between the bulk and edges in a minimal system, by engineering a three-site Kitaev chain in a two-dimensional electron gas. Through direct tunneling spectroscopy on each site, we show that the appearance of stable zero-bias conductance peaks at the outer QDs is correlated with the presence of an excitation gap in the middle QD. Furthermore, we show that this gap can be controlled by applying a superconducting phase difference between the two hybrid segments and that the MBSs are robust only when the excitation gap is present. We find a close agreement between experiments and the original Kitaev model, thus confirming key predictions for MBSs in a three-site chain.
format Preprint
id arxiv_https___arxiv_org_abs_2410_00658
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Observation of edge and bulk states in a three-site Kitaev chain
Haaf, Sebastiaan L. D. ten
Zhang, Yining
Wang, Qingzhen
Bordin, Alberto
Liu, Chun-Xiao
Kulesh, Ivan
Sietses, Vincent P. M.
Prosko, Christian G.
Xiao, Di
Thomas, Candice
Manfra, Michael J.
Wimmer, Michael
Goswami, Srijit
Mesoscale and Nanoscale Physics
Superconductivity
A chain of quantum dots (QDs) in semiconductor-superconductor hybrid systems can form an artificial Kitaev chain hosting Majorana bound states (MBSs). These zero-energy states are expected to be localised on the edges of the chain, at the outermost QDs. The remaining QDs, comprising the bulk, are predicted to host an excitation gap that protects the MBSs at the edges from local on-site perturbations. Here we demonstrate this connection between the bulk and edges in a minimal system, by engineering a three-site Kitaev chain in a two-dimensional electron gas. Through direct tunneling spectroscopy on each site, we show that the appearance of stable zero-bias conductance peaks at the outer QDs is correlated with the presence of an excitation gap in the middle QD. Furthermore, we show that this gap can be controlled by applying a superconducting phase difference between the two hybrid segments and that the MBSs are robust only when the excitation gap is present. We find a close agreement between experiments and the original Kitaev model, thus confirming key predictions for MBSs in a three-site chain.
title Observation of edge and bulk states in a three-site Kitaev chain
topic Mesoscale and Nanoscale Physics
Superconductivity
url https://arxiv.org/abs/2410.00658