Superhard and Superconducting Bilayer Borophene

Chengyong Zhong; Minglei Sun; Tariq Altalhi; Boris I Yakobson

doi:10.3390/ma17091967

Superhard and Superconducting Bilayer Borophene

Materials (Basel). 2024 Apr 24;17(9):1967. doi: 10.3390/ma17091967.

Authors

Chengyong Zhong¹, Minglei Sun², Tariq Altalhi³, Boris I Yakobson^{3

4}

Affiliations

¹ College of Physics and Electronic Engineering, Chongqing Normal University, Chongqing 401331, China.
² Department of Materials Science and Nanoengineering, Rice University, Houston, TX 77005, USA.
³ Chemistry Department, Taif University, Taif 21974, Saudi Arabia.
⁴ Department of Chemistry, Rice University, Houston, TX 77005, USA.

Abstract

Two-dimensional superconductors, especially the covalent metals such as borophene, have received significant attention due to their new fundamental physics, as well as potential applications. Furthermore, the bilayer borophene has recently ignited interest due to its high stability and versatile properties. Here, the mechanical and superconducting properties of bilayer-δ6 borophene are explored by means of first-principles computations and anisotropic Migdal-Eliashberg analytics. We find that the coexistence of strong covalent bonds and delocalized metallic bonds endows this structure with remarkable mechanical properties (maximum 2D-Young's modulus of ~570 N/m) and superconductivity with a critical temperature of ~20 K. Moreover, the superconducting critical temperature of this structure can be further boosted to ~46 K by applied strain, which is the highest value known among all borophenes or two-dimensional elemental materials.

Keywords: anisotropic superconductivity; bilayer borophene; electron–phonon coupling; first-principles calculations; strain effect; superhard.

Grants and funding

C.Z. acknowledges the financial support from the Scientific and Technology Research Program of Chongqing Municipal Education Commission (KJQN202300515) and the Foundation of Chongqing Normal University (23XLB001). T.A. and B.I.Y. acknowledge the Taif University Research Support Project (TURSPHC2024/1, Saudi Arabia). Work at Rice was supported by the US Office of Naval Research (N00014-22-1-2753).