Superconductivity in Bismuth. A New Look at an Old Problem

PLoS One. 2016 Jan 27;11(1):e0147645. doi: 10.1371/journal.pone.0147645. eCollection 2016.

Abstract

To investigate the relationship between atomic topology, vibrational and electronic properties and superconductivity of bismuth, a 216-atom amorphous structure (a-Bi216) was computer-generated using our undermelt-quench approach. Its pair distribution function compares well with experiment. The calculated electronic and vibrational densities of states (eDOS and vDOS, respectively) show that the amorphous eDOS is about 4 times the crystalline at the Fermi energy, whereas for the vDOS the energy range of the amorphous is roughly the same as the crystalline but the shapes are quite different. A simple BCS estimate of the possible crystalline superconducting transition temperature gives an upper limit of 1.3 mK. The e-ph coupling is more preponderant in a-Bi than in crystalline bismuth (x-Bi) as indicated by the λ obtained via McMillan's formula, λc = 0.24 and experiment λa = 2.46. Therefore with respect to x-Bi, superconductivity in a-Bi is enhanced by the higher values of λ and of eDOS at the Fermi energy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bismuth*
  • Computer Simulation
  • Electric Conductivity*
  • Models, Theoretical

Substances

  • Bismuth

Grants and funding

This work was supported by Dirección General de Asuntos del Personal Académico, UNAM. Proyecto IN110914, “Simulando materiales metálicos amorfos. Su estructura y propiedades físicas.