Prediction of high-Tc superconductivity in ternary actinium beryllium hydrides at low pressure

Abstract

Hydrogen-rich superconductors are promising candidates to achieve room-temperature superconductivity. However, the extreme pressures needed to stabilize these structures significantly limit their practical applications. An effective strategy to reduce the external pressure is to add a light element M that binds with H to form MHx units, acting as a chemical precompressor. We exemplify this idea by performing ab initio calculations of the Ac-Be-H phase diagram, proving that the metallization pressure of Ac-H binaries, for which critical temperatures as high as 200 K were predicted at 200 GPa, can be significantly reduced via beryllium incorporation. We identify three thermodynamically stable (AcBe2H10, AcBeH8, and AcBe2H14) and four metastable compounds (fcc AcBeH8, AcBeH10, AcBeH12 and AcBe2H16). All of them are superconductors. In particular, fcc AcBeH8 remains dynamically stable down to 10 GPa, where it exhibits a superconducting transition temperature Tc of 181 K. The Be-H bonds are responsible for the exceptional properties of these ternary compounds and allow them to remain dynamically stable close to ambient pressure. Our results suggest that high-Tc superconductivity in hydrides is achievable at low pressure and may stimulate experimental synthesis of ternary hydrides.

References in corpus (7)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Superconductive "sodalite"-like clathrate calcium hydride at high pressures
• Superconductivity to 262 kelvin via catalyzed hydrogenation of yttrium at high pressures
• Prediction of high-Tc superconductivity in ternary lanthanum borohydrides
• Phonon-mediated high-temperature superconductivity in ternary borohydride KB${}_2$H${}_8$ around 12 GPa
• In-silico synthesis of lowest-pressure high-$T_{\text{c}}$ ternary superhydrides
• Superconductivity in CeBeH${}_8$ and CeBH${}_8$ at moderate pressures

Cited by in corpus (5)

• Prediction of high-Tc superconductivity under submegabar pressure in ternary actinium borohydrides
• A-15 type superconducting hydride $L{a}_4{H}_{23}$: Nanograined structure with low strain, strong electron-phonon interaction, and moderate level of nonadiabaticity
• Theoretical prediction of strong-coupling superconductivity in a hypothetical NaAlH3 phase at ambient pressure
• Superconducting ternary compounds Li-X-B (X=Mo, W) within the mild pressure range: First-principles predictions
• Composition-Based Machine Learning for Screening Superconducting Ternary Hydrides from a Curated Dataset