Single layer clathrane: A potential superconducting two-dimensional (2D) hydrogenated metal borocarbide

Xiaoyu Wang; Warren E. Pickett; Matthew N. Julian; Rohit P. Prasankumar; Eva Zurek

doi:10.1021/acs.nanolett.5c04166

paper

Single layer clathrane: A potential superconducting two-dimensional (2D) hydrogenated metal borocarbide

arXiv:2508.14371 · doi:10.1021/acs.nanolett.5c04166

Abstract

We propose a new family of two-dimensional (2D) metal-borocarbide clathrane superconductors, derived from three-dimensional (3D) MM $^{'}$ B $_{6}$ C $_{6}$ clathrates. First-principles calculations reveal that hydrogen passivation and surface metal decoration stabilize the M $_{2}$ M $^{'}$ B $_{8}$ C $_{8}$ H $_{8}$ 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 \tc\ despite favorable doping. Biaxial strain mitigates this anisotropy, enhances Fermi surface nesting, and increases \tc\ by an average of 15.5~K. For example, the \tc\ of Sr $_{3}$ B $_{8}$ C $_{8}$ H $_{8}$ is predicted to increase from 11.3~K 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.