Superconductivity in two-dimensional materials

Datum: 24 september 2019

Locatie: Campus Groenenborger, Building U, Room 244 - Groenenborgerlaan 171 - 2020 Antwerpen (route: UAntwerpen, Campus Groenenborger)

Tijdstip: 16 - 17 uur

Organisatie / co-organisatie: Condensed Matter Theory

Korte beschrijving: CMT lecture presented by Dr Jonas Bekaert

Abstract
Although seemingly prohibited by the Mermin-Wagner theorem, the superconducting state has now been realized in a wide variety of two-dimensional (2D) materials [1], down to atomic sheets such as decorated and twisted (bilayer) graphene [2]. I will first review some key aspects that make 2D superconductivity particularly interesting, such as topological
phase transitions, the interplay with other 2D quantum states and the ability to tailor the superconducting properties through nanoengineering. In the second part of the talk I will demonstrate the important role of theory in exploring these properties. Here, I will focus on describing phonon-mediated 2D superconductivity within a quantum field theory extension of the Bardeen-Cooper-Schrieffer theory, in combination with first-principles calculations of the electron-phonon interaction [3-5]. Based on this methodology I will show how the 2D superconducting critical temperature can be strongly enhanced by means of multiband electronic effects [3-4], strain [4] and adatoms [5].

References

  • [1] Y. Saito et al., Nat. Rev. Mater. 2, 16094 (2016); T. Uchihashi, Supercond. Sci. Technol. 30, 013002 (2017); C. Brun et al., Supercond. Sci. Technol. 30, 013003 (2017)
  • [2] G. Profeta et al., Nat. Phys. 8, 131 (2012); Y. Cao et al., Nature 556, 43 (2018)
  • [3] J. Bekaert et al., Sci. Rep. 7, 14458 (2017)
  • [4] J. Bekaert et al., Phys. Rev. B 96, 094510 (2017)
  • [5] J. Bekaert et al., Phys. Rev. Lett. 123, 077001 (2019)


Contact e-mail: lucian.covaci@uantwerpen.be

Link: http://cmt.uantwerpen.be