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arXiv · 1708.03483

Superconductivity in SrB3C3 clathrate

Li Zhu·Hanyu Liu·Maddury Somayazulu·Yue Meng·Piotr A. Guńka·Thomas B. Shiell·Curtis Kenney-Benson·Stella Chariton·Vitali B. Prakapenka·Hyeok Yoon·Jarryd A. Horn·Johnpierre Paglione·Roald Hoffmann·R. E. Cohen·Timothy A. Strobel
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Abstract

We predict superconductivity for the carbon-boron clathrate SrB3C3 at 27-43 K for Coulomb pseudopotential (mu*) values between 0.17 and 0.10 using first-principles calculations with conventional electron-phonon coupling. Electrical transport measurements, facilitated by a novel in situ experimental design compatible with extreme synthesis conditions (>3000 K at 50 GPa), show non-hysteretic resistivity drops that track the calculated magnitude and pressure dependence of superconductivity for mu*=0.15, and transport measurements collected under applied magnetic fields confirm superconductivity with an onset Tc of approximately 20 K at 40 GPa. Carbon-based clathrates thus represent a new class of superconductors similar to other covalent metals like MgB2 and doped fullerenes. Carbon clathrates share structures similar to superconducting superhydrides, but covalent C-B bonds allow metastable persistence at ambient conditions.

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Li Zhu, Hanyu Liu, Maddury Somayazulu, Yue Meng, Piotr A. Guńka, Thomas B. Shiell, Curtis Kenney-Benson, Stella Chariton, Vitali B. Prakapenka, Hyeok Yoon, Jarryd A. Horn, Johnpierre Paglione, Roald Hoffmann, R. E. Cohen, Timothy A. Strobel. 2017-08-11. Superconductivity in SrB3C3 clathrate. https://arxiv.org/abs/1708.03483

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