Prediction of phonon-mediated high-T<sub>C</sub> superconductivity in monolayer Mg<sub>2</sub>B<sub>4</sub>C<sub>2</sub>

ORAL

Abstract

We theoretically design a novel two-dimensional material - Mg2B4C2, which is predicted to exhibit superconductivity with critical temperature TC estimated in the 67-84 K range (predicted using the isotropic Migdal-Eliashberg theory) without any tuning of external parameters such as doping, strain, or substrate-induced effects. This 2D material is stable and it belongs to the family of the conventional high-TC bulk superconductor MgB2. It is obtained after replacing the chemically active boron layers in MgB2 with chemically inactive boron-carbon layers. The key feature in 2D Mg2B4C2 is the fact that, unlike in bulk MgB2, more than just two E2g phonon modes strongly couple to the electronic states near the Fermi level, thus resulting in a substantially large electron-phonon coupling (λ = 1.75), as compared to the bulk MgB2 (λbulk = 0.6-0.7). This material also features a topologically nontrivial electronic bandstructure (Dirac metal). Interestingly, we find that the key features of this material remain essentially unchanged when its thickness is increased by modestly increasing the number of inner MgB2 layers.

*Support from ONR Grants N00014-19-1-2073 and N00014-16-1-2951, Fondecyt Grant #1191353, DMREF-NSF 1434897, NSF OAC-1740111, and DOE DE-SC0016176 projects is acknowledged.

–

Presenters

  • Sobhit Singh

    • Rutgers, The State University of New Jersey
    • Department of Physics and Astronomy, Rutgers University
    • Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA

Authors

  • Sobhit Singh

    • Rutgers, The State University of New Jersey
    • Department of Physics and Astronomy, Rutgers University
    • Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA

  • Aldo H. Romero

    • Department of Physics and Astronomy, West Virginia University, Morgantown, WV, USA

  • José D. Mella

    • Departamento de Fìsica, Facultad de Ciencias, Universidad de Chile, Santiago, Chile

  • Vitalie Eremeev

    • Instituto de Ciencias Bàsicas, Facultad de Ingenierìa y Ciencias, Universidad Diego Portales, Santiago, Chile

  • Enrique Munoz

    • Institute of Physics, Pontificia Universidad Catòlica de Chile, Santiago, Chile

  • Anastassia N. Alexandrova

    • Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA

  • Karin M Rabe

    • Rutgers University, New Brunswick
    • Rutgers, The State University of New Jersey
    • Dept. of Physics and Astronomy, Rutgers University, New Brunswick
    • Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA

  • David Vanderbilt

    • Rutgers University, New Brunswick
    • Rutgers University
    • Physics, Rutger Univeristy
    • Department of Physics and Astronomy, Rutgers University
    • Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA

  • Francisco Muñoz

    • Department of Physics, University of Chile
    • Departamento de Fìsica, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
    • University of Chile