Skip to main content
SpringerLink
Log in

BCS-BEC Crossover in Quantum Confined Superconductors

  • Original Paper
  • Published:
Journal of Superconductivity and Novel Magnetism Aims and scope Submit manuscript

Abstract

Ultranarrow superconductors are in the strong quantum confinement regime with formation of multiple coherent condensates associated with the many subbands of the electronic structure. Here, we analyze the multiband BCS-BEC crossover induced by the chemical potential tuned close to a subband bottom, in correspondence of a superconducting shape resonance. The evolution of the condensate fraction and of the pair correlation length in the ground state as functions of the chemical potential demonstrates the tunability of the BCS-BEC crossover for the condensate component of the selected subband. The extension of the crossover regime increases when the pairing strength and/or the characteristic energy of the interaction get larger. Our results indicate the coexistence of large and small Cooper pairs in the crossover regime, leading to the optimal parameter configuration for high transition temperature superconductivity.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4

Similar content being viewed by others

References

  1. Blatt, J.M.: Theory of Superconductivity. Academic Press, New York (1964)

    MATH  Google Scholar 

  2. Perali, A., Bianconi, A., Lanzara, A., Saini, N.L.: The gap amplification at a shape resonance in a superlattice of quantum stripes: a mechanism for high Tc. Solid State Commun. 100, 181–186 (1996)

    Article  ADS  Google Scholar 

  3. Bianconi, A., Valletta, A., Perali, A., Saini, N.L.: High Tc superconductivity in a superlattice of quantum stripes. Solid State Commun. 102, 369–374 (1997)

    Article  ADS  Google Scholar 

  4. Shanenko, A.A., Croitoru, M.D., Zgirski, M., Peeters, F.M., Arutyunov, K.: Size-dependent enhancement of superconductivity in nanowires. Phys. Rev. B 74((4pp)), 052502 (2006). and references therein

    Article  ADS  Google Scholar 

  5. Bianconi, A., Valletta, A., Perali, A., Saini, N.L.: Superconductivity of a striped phase at the atomic limit. Physica C. 296, 269–280 (1998)

    Article  ADS  Google Scholar 

  6. Chen, Y.J., Shanenko, A.A., Perali, A., Peeters, F.M.: Superconducting nanofilms: molecule-like pairing induced by quantum confinement. Journal of Phys.:Condens. Matter 24(8pp), 185701 (2012)

    ADS  Google Scholar 

  7. Shanenko, A.A., Croitoru, M.D., Vagov, A.V., Axt, V.M., Perali, A., Peeters, F.M.: Atypical BCS-BEC crossover induced by quantum-size effects. Phys. Rev. A 86(7pp), 033612 (2012)

    Article  ADS  Google Scholar 

  8. Milosevic, M.V., Perali, A.: Emergent phenomena in multicomponent superconductivity: an introduction to the focus issue. Supercond. Sci. Technol. 28(4pp), 060201 (2015). and references therein

    Article  ADS  Google Scholar 

  9. Caivano, R., Fratini, M., Poccia, N., Ricci, A., Puri, A., Ren, Z.-A., Dong, X.-L., Yang, J., Lu, W., Zhao, Z.-X., Barba, L., Bianconi, A.: Feshbach resonance and mesoscopic phase separation near a quantum critical point in multiband FeAs-based superconductors. Supercond. Sci. Technol 22(12pp), 014004 (2009)

    Article  ADS  Google Scholar 

  10. Bianconi, A.: Feshbach shape resonance in multiband superconductivity in heterostructures. Journal of Superconductivity 18, 625–636 (2005)

    Article  ADS  Google Scholar 

  11. Lubashevsky, Y., Lahoud, E., Chashka, K., Podolsky, D., Kanigel, A.: Shallow pockets and very strong coupling superconductivity in FeSe x Te1−x . Nature Phys. 8, 309–312 (2012)

    Article  ADS  Google Scholar 

  12. Kasahara, S.,Watashige, T., Hanaguri, T., Kohsaka, Y., Yamashita, T., Shimoyama, Y., Mizukami, Y., Endo, R., Ikeda, H., Aoyama, K., Terashima, T., Uji, S., Wolf, T., Löhneysenn, H.v., Shibauchi, T., Matsuda, Y.: Field-induced superconducting phase of FeSe in the BCS-BEC cross-over. PNAS 111, 16309–16313 (2014)

  13. Bianconi, A.: Quantum materials: shape resonances in superstripes. Nature Phys. 9, 536–537 (2013)

    Article  ADS  MathSciNet  Google Scholar 

  14. Perali, A., Palestini, F., Pieri, P., Strinati, G.C., Stewart, J.T., Gaebler, J.P., Drake, T.E., Jin, D.S.: Evolution of the normal state of a strongly interacting Fermi gas from a pseudogap phase to a molecular Bose gas. Phys. Rev. Lett. 106(4pp), 060402 (2011)

    Article  ADS  Google Scholar 

  15. Pieri, P., Perali, A., Strinati, G.C., Riedl, S., Wright, M.J., Altmeyer, A., Kohstall, C., Sánchez Guajardo, E.R., Hecker Denschlag, J., Grimm, R.: Pairing-gap, pseudo-gap, and no-gap phases in the radio-frequency spectra of a trapped unitary 6Li gas. Phys. Rev. A 84, 011608(R) (4pp) (2011)

    Article  ADS  Google Scholar 

  16. Palestini, F., Perali, A., Pieri, P., Strinati, G.C.: Dispersions, weights, and widths of the single-particle spectral function in the normal phase of a Fermi gas. Phys. Rev. B 85(17pp), 024517 (2012)

    Article  ADS  Google Scholar 

  17. Guidini, A., Perali, A.: Band-edge BCS-BEC crossover in a two-band superconductor: physical properties and detection parameters. Supercond. Sci. Technol. 27(10pp), 124002 (2014)

    Article  ADS  Google Scholar 

  18. Perali, A., Castellani, C., Di Castro, C., Grilli, M., Piegari, E., Varlamov, A.A.: Two-gap model for underdoped cuprate superconductors. Phys. Rev. B 62, R9295(R) (4pp) (2000)

    ADS  Google Scholar 

  19. Geurts, R., Milosevic, M.V., Peeters, F.M.: Vortex matter in mesoscopic two-gap superconducting disks: Influence of Josephson and magnetic coupling. Phys. Rev. B 81(15pp), 214514 (2010)

    Article  ADS  Google Scholar 

  20. Chaves, A., Komendová, L., Milosevic, M.V., Andrade Jr., J.S., Farias, G.A., Peeters, F.M.: Conditions for nonmonotonic vortex interaction in two-band superconductors. Phys. Rev. B 83(6pp), 214523 (2011)

    Article  ADS  Google Scholar 

  21. Komendová, L., Chen, Y., Shanenko, A.A, Milosevic, M.V., Peeters, F.M.: Two-Band Superconductors: Hidden Criticality Deep in the Superconducting State. Phys. Rev. Lett 108(5pp), 207002 (2012)

    Article  ADS  Google Scholar 

  22. Pistolesi, F., Strinati, G.C.: Evolution from BCS superconductivity to Bose condensation: role of the parameter k F ξ. Phys. Rev. B 49(4pp), 6356 (1994)

    Article  ADS  Google Scholar 

Download references

Acknowledgments

We acknowledge A. Bianconi and A.A. Shanenko for useful discussions. A.P. acknowledges financial support from the University of Camerino under the project FAR “Control and enhancement of superconductivity by engineering materials at the nanoscale”. M.V.M. acknowledges support from the Research Foundation - Flanders (FWO) and the Special Research Funds of the University of Antwerp (BOF-UA). A.P. and M.V.M. acknowledge the collaboration within the MultiSuper International Network (http://www.multisuper.org) for exchange of ideas and suggestions.

Author information

Authors and Affiliations

  1. School of Science and Technology, Physics Division, University of Camerino, 62032, Camerino, Italy

    Andrea Guidini & Luca Flammia

  2. Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020, Antwerpen, Belgium

    Luca Flammia & Milorad V. Milošević

  3. School of Pharmacy, Physics Unit, University of Camerino, 62032, Camerino, Italy

    Andrea Perali

Authors
  1. Andrea Guidini
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Luca Flammia
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Milorad V. Milošević
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Andrea Perali
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Andrea Perali.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Guidini, A., Flammia, L., Milošević, M.V. et al. BCS-BEC Crossover in Quantum Confined Superconductors. J Supercond Nov Magn 29, 711–715 (2016). https://doi.org/10.1007/s10948-015-3308-y

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10948-015-3308-y

Keywords

Search

Navigation