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Toward ambient-pressure superconductivity from boron icosahedral superatoms

Simone Di Cataldo1,*, Antonio Sanna2,3, and Lilia Boeri1

  • *Contact author: simone.dicataldo@uniroma1.it
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Phys. Rev. B 114, 154507 – Published 11 September, 2026

DOI: https://doi.org/10.1103/yvcr-2yj8

Abstract

We identify a family of boron-rich compounds consisting of interconnected B12 icosahedra and electropositive guest atoms (X) in interstitial sites. These structures were found through first-principles crystal structure prediction at 50 GPa, and are dynamically stable down to ambient pressure. When X is a mono- or trivalent element, the structures are metallic and superconducting. Predicted critical temperatures reach up to 42 K for CsB12, rivaling MgB2, the highest-Tc ambient-pressure conventional superconductor. We interpret the XB12 phase as a superatomic crystal: the B12 units retain the icosahedral shape that they also exhibit in isolation, while forming an extended crystalline network. When X is a mono- or trivalent atom, the system is metallic, and the B–B covalent bonding promotes strong electron-phonon coupling. Unlike MgB2, where superconductivity is driven by a narrow subset of phonon modes, the XB12 compounds exhibit broad, mode- and momentum-distributed coupling through both intra- and intersuperatomic vibrations. Our results highlight the XB12 family as a promising platform for superconductivity and demonstrate the potential of superatoms as functional building blocks in solid-state materials design.

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Phys. Rev. B 114, 154507– Published 11 September, 2026
  • Received 14 May 2026
  • Revised 24 July 2026
  • Accepted 21 August 2026
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