Single-Layer Clathrane: A Potential Superconducting Two-Dimensional Hydrogenated Metal Borocarbide.

Wang, Xiaoyu; Pickett, Warren E; Julian, Matthew N; Prasankumar, Rohit P; Zurek, Eva · Nano Lett · 2025

basic_science · Level V

Where this comes from

Abstract

We propose a new family of two-dimensional (2D) metal borocarbide clathrane superconductors derived from three-dimensional (3D) MM'B<sub>6</sub>C<sub>6</sub> clathrates. First-principles calculations reveal that hydrogen passivation and surface metal decoration stabilize the M<sub>2</sub>M'B<sub>8</sub>C<sub>8</sub>H<sub>8</sub> monolayers. These 2D systems exhibit tunable superconductivity governed by hole concentration, structural anisotropy, and electron-phonon coupling. We find that in-plane anisotropy competes with superconductivity, reducing <i>T</i><sub>c</sub> despite favorable doping. Biaxial strain mitigates this anisotropy, enhances Fermi surface nesting, and increases <i>T</i><sub>c</sub> by an average of 15.5 K. For example, the <i>T</i><sub>c</sub> of Sr<sub>3</sub>B<sub>8</sub>C<sub>8</sub>H<sub>8</sub> is predicted to increase from 11.3 to 22.2 K with strain engineering. These findings identify 2D clathranes as promising, strain-tunable superconductors and highlight design principles for optimizing low-dimensional superconducting materials.