Probing Majorana bound states via a pn junction containing a quantum dot

authored by: L. Bittermann, C. De Beule, D. Frombach, P. Recher
Abstract: We propose an alternative route to transport experiments for detecting Majorana bound states (MBSs) by combining topological superconductivity with quantum optics in a superconducting pn junction containing a quantum dot (QD). We consider a topological superconductor (TSC) hosting two Majorana bound states at its boundary (n side). Within an effective low-energy model, the MBSs are coherently tunnel-coupled to a spin-split electron level on the QD, which is placed close to one of the MBSs. Holes on the QD are tunnel-coupled to a normal conducting reservoir (p side). Via electron-hole recombination, photons in the optical range are emitted, which have direct information on the MBS properties through the recombined electrons. Using a master equation approach, we calculate the polarization-resolved photon emission intensities (PEIs). In the weak coupling regime between MBSs and QD, we find an analytical expression for the PEI which allows to clearly distinguish the cases of well separated MBSs at zero energy from overlapping MBSs. For separated MBSs, the Majorana spinor polarization is given by the relative widths of the two PEI peaks associated with the two spin states on the QD. For overlapping MBSs, a coupling to the distant (nonlocal) MBS causes a shift of the emission peaks. Additionally, we show that quasiparticle poisoning (QP) influences the PEI drastically and changes its shot noise from super-Poissonian to sub-Poissonian. In the strong coupling regime, more resonances emerge in the PEI due to spin-mixing effects. Finally, we comment on how our proposal could be implemented using a Majorana nanowire.
External Organisation(s): Technische Universität Braunschweig
University of Luxembourg
Laboratory for Emerging Nanometrology Braunschweig (LENA)
Type: Article
Journal: Physical Review B
Volume: 106
ISSN: 2469-9950
Publication date: 18.08.2022
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Condensed Matter Physics
Electronic version(s): https://doi.org/10.1103/PhysRevB.106.075305 (Access: Unknown)

BibTeX

@article{9bd4b6da785b466980968a075f8f620d,
title = "Probing Majorana bound states via a pn junction containing a quantum dot",
abstract = "We propose an alternative route to transport experiments for detecting Majorana bound states (MBSs) by combining topological superconductivity with quantum optics in a superconducting pn junction containing a quantum dot (QD). We consider a topological superconductor (TSC) hosting two Majorana bound states at its boundary (n side). Within an effective low-energy model, the MBSs are coherently tunnel-coupled to a spin-split electron level on the QD, which is placed close to one of the MBSs. Holes on the QD are tunnel-coupled to a normal conducting reservoir (p side). Via electron-hole recombination, photons in the optical range are emitted, which have direct information on the MBS properties through the recombined electrons. Using a master equation approach, we calculate the polarization-resolved photon emission intensities (PEIs). In the weak coupling regime between MBSs and QD, we find an analytical expression for the PEI which allows to clearly distinguish the cases of well separated MBSs at zero energy from overlapping MBSs. For separated MBSs, the Majorana spinor polarization is given by the relative widths of the two PEI peaks associated with the two spin states on the QD. For overlapping MBSs, a coupling to the distant (nonlocal) MBS causes a shift of the emission peaks. Additionally, we show that quasiparticle poisoning (QP) influences the PEI drastically and changes its shot noise from super-Poissonian to sub-Poissonian. In the strong coupling regime, more resonances emerge in the PEI due to spin-mixing effects. Finally, we comment on how our proposal could be implemented using a Majorana nanowire.",
author = "L. Bittermann and {De Beule}, C. and D. Frombach and P. Recher",
note = "Funding information: We thank V. Zwiller for comments on the manuscript and F. Dominguez for fruitful discussions related to the shot noise considerations. L.B., D.F., and P.R. acknowledge financial support by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) within the framework of Germany's Excellence Strategy-EXC-2123 QuantumFrontiers-390837967 and L.B. and P.R. acknowledge financial support from Nieders{\"a}chsisches Vorab through Quantum- and Nano-Metrology (QUANOMET) initiative within the project NL-2.",
year = "2022",
month = aug,
day = "18",
doi = "10.1103/PhysRevB.106.075305",
language = "English",
volume = "106",
journal = "Physical Review B",
issn = "2469-9950",
publisher = "American Institute of Physics",
number = "7",
}