Hydrogen-induced high-temperature superconductivity in two-dimensional materials: Example of hydrogenated monolayer MgB₂

2019/02/11 by Jonas Bekaert, Mikhail Petrov, Alex Aperis +2 · 1 citation
Physics and Astronomy · #cond-mat.supr-con

paper · pdf · doi:10.1103/physrevlett.123.077001

published as Phys. Rev. Lett. 123, 077001 (2019)

arxiv created 2019/02/11 · arxiv updated 2019/08/21

Abstract

Hydrogen-based compounds under ultra-high pressure, such as the polyhydrides H₃S and LaH₁₀, superconduct through the conventional electron-phonon coupling mechanism to attain the record critical temperatures known to date. We demonstrate here that the intrinsic advantages of hydrogen for phonon-mediated superconductivity can be exploited in a completely different system, namely two-dimensional (2D) materials. We find that hydrogen adatoms can strongly enhance superconductivity in 2D materials due to flatband states originating from atomic-like hydrogen orbitals, with a resulting high density of states, and due to the emergence of high-frequency hydrogen-related phonon modes that boost the electron-phonon coupling. As a concrete example, we investigate the effect of hydrogen adatoms on the superconducting properties of monolayer MgB₂, by solving the fully anisotropic Eliashberg equations, in conjunction with a first-principles description of the electronic and vibrational states, and the coupling between them. We show that hydrogenation leads to a high critical temperature of 67 K, which can be boosted to over 100 K by biaxial tensile strain.

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