Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                

Shedding light on topological superconductors

K. H. A. Villegas, V. M. Kovalev, F. V. Kusmartsev, and I. G. Savenko
Phys. Rev. B 98, 064502 – Published 7 August 2018
PDFHTMLExport Citation
Abstract
Authors
Article Text
  • INTRODUCTION
  • SYSTEM SCHEMATIC AND HYBRID EIGENMODES
  • ELECTROMAGNETIC POWER ABSORPTION BY 2DEG
  • ELECTROMAGNETIC POWER ABSORPTION BY…
  • DISCUSSION
  • CONCLUSIONS
  • ACKNOWLEDGMENTS
  • APPENDICES
    • References

    Abstract

    We propose an effective optical approach to monitor superconductors in a two-layer superconductor-normal metal structure. Effectively, such a hybrid system represents a resonator, where electrons are strongly coupled with light. We show that the interaction of light with the superconductor is strongly boosted in the presence of the neighboring metal and, as a result, the electromagnetic power absorption of the system is dramatically enhanced. It manifests itself in a giant Fano-type resonance which can uniquely characterize the elementary excitations of the system. Our approach is especially promising for topological superconductors, where Majorana fermions could be revealed and controlled by light.

    • Figure
    • Figure
    • Figure
    • Figure
    • Figure
    • Figure
    • Figure
    • Received 27 April 2018
    • Revised 13 July 2018

    DOI:https://doi.org/10.1103/PhysRevB.98.064502

    ©2018 American Physical Society

    Physics Subject Headings (PhySH)

    1. Research Areas
    Superconducting fluctuationsSuperconducting phase transitionSuperconducting quantum opticsTopological superconductors
    1. Physical Systems
    HeterostructuresLow-temperature superconductorsSuperconductorsUnconventional superconductors
    1. Techniques
    Methods in superconductivityOptical absorption spectroscopy
    Condensed Matter, Materials & Applied Physics

    Authors & Affiliations

    K. H. A. Villegas1, V. M. Kovalev2,3, F. V. Kusmartsev4,5, and I. G. Savenko1,6

    • 1Center for Theoretical Physics of Complex Systems, Institute for Basic Science (IBS), Daejeon 34126, Korea
    • 2A.V. Rzhanov Institute of Semiconductor Physics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
    • 3Department of Applied and Theoretical Physics, Novosibirsk State Technical University, Novosibirsk 630073, Russia
    • 4Department of Physics, Loughborough University, Loughborough LE11 3TU, United Kingdom
    • 5Micro/Nano Fabrication Laboratory Microsystem and THz Research Center, Chengdu, Sichuan, China
    • 6Basic Science Program, Korea University of Science and Technology (UST), Daejeon 34113, Korea

    Article Text (Subscription Required)

    Click to Expand

    References (Subscription Required)

    Click to Expand
    Issue

    Vol. 98, Iss. 6 — 1 August 2018

    Reuse & Permissions
    Access Options
    Author publication services for translation and copyediting assistance advertisement

    Authorization Required

    Log In
    Other Options
    ×

    Images

    • Figure 1
      Figure 1

      System schematic. (a) Hybrid normal-metal–superconductor structure exposed to an electromagnetic field of incident light. (b) Dispersions of hybrid eigenmodes of the system: ω as a function of k for mN=mS=1 (green and blue solid curves). The dashed curves of the corresponding colors show the individual modes of each layer when the interlayer interaction is switched off. (c) Schematic of in-layer, interlayer, and light-matter interactions in the system manifesting itself in fluctuations of electron and Cooper pair densities, δn and δN, and polarization operators Fkω, Gkω, and Πkω. (d) Spectrum of electromagnetic power absorption demonstrating the Fano resonance profile.

      Reuse & Permissions
    • Figure 2
      Figure 2

      Spectra. Power absorption monitored in 2DEG [(a), (b)] and superconductor [(c), (d)] as a function of ω for Δ=1.0 meV. Vertical dashed lines stand for the corresponding locations of the hybrid modes [within Eq. (1)]. (a) k=1.0×10−3 (red curve), 1.0×10−2 (green curve), and 1.0×10−1 meV (blue curve). Inset shows the range 0≤ω<2Δ, contributions to P1(ω) due to single-particle excitations. To render these contributions visible, larger k's were used: k=5.0×101 (red curve), 5.0×102 (green curve), and 1.0×103 (blue curve). (b) k=1.0×101 (red curve), 1.0×102 (green curve), and 1.0×103 meV (blue curve). Inset shows the case with no interlayer interaction. (c) Both layers are exposed to the EMF. Inset: zoom-in for small ω's showing peaks caused by the lower hybrid modes. (d) No external field on the normal layer. Inset shows the log plot of the corresponding blue curve, manifesting the two peaks and the dip of the Fano resonance. In (c) and (d), k=1.0×101 (red curves), 1.0×102 (green curves), 1.0×103 meV (blue curves). Dashed black curves in (d) show the case when interlayer coupling is turned off.

      Reuse & Permissions
    • Figure 3
      Figure 3

      Spectrum in topologically nontrivial case. Power absorption (in log scale) monitored in superconductor as a function of ω at k=0.5×10−1 meV (red) and k=1.0×10−1 meV (green).

      Reuse & Permissions
    • Figure 4
      Figure 4

      Power absorption spectrum when the interlayer interaction is turned off. (a) Current is monitored in the 2DEG. (b) Current is monitored in the superconductor.

      Reuse & Permissions
    • Figure 5
      Figure 5

      Power absorption as a function of ω when there is no external EM field on the superconductor layer for k=1.0 (red), 5.0×101 (green), 1.0×102 meV (blue). Inset: zoom-in for 50≤ω<200 meV and 400≤ω<800.

      Reuse & Permissions
    • Figure 6
      Figure 6

      Power absorption for mN=me and the effective electron mass in superconducting layer varied: mS=0.5me (red), mS=me (green), mS=10me (blue). Upper panels: current is monitored in the 2DEG with EM field present in (a) both layers and (b) 2DEG layer only. Lower two panels: current is monitored in the superconductor with EM field present in (c) both layers and (d) 2DEG layer only. Zoom-in for 0≤ω<14 meV and 200≤ω<1500.

      Reuse & Permissions
    • Figure 7
      Figure 7

      Power absorption in the case when the interlayer spacing is varied (in eV−1): 1.0×10−2 (red), 5.0×10−2 (green), and 1.0×10−1 (blue). Upper panels: current monitored in the 2DEG with EM field present in (a) both layers and (b) 2DEG layer only. Lower panels: current is monitored in the superconductor with EM field present in (c) both layers and (d) 2DEG layer only.

      Reuse & Permissions
    ×

    Sign up to receive regular email alerts from Physical Review B

    Log In

    Cancel
    ×

    Search

    Article Lookup

    Paste a citation or DOI
    Enter a citation
    ×