Dilute carbon in H3S under pressure

• DOI: 10.1038/s41524-022-00769-9
• Publication Date: 2022-04-27T10:03:29Z
• Authors: Xiaoyu Wang; Tiange Bi; Katerina P. Hilleke; Anmol Lamichhane; Russell J. Hemley; Eva Zurek
• Keywords: QA76.75-76.765; 0303 health sciences; 03 medical and health sciences; TA401-492; Computer software; Materials of engineering and construction. Mechanics of materials; 7. Clean energy

AbstractRecently, room temperature superconductivity was measured in a carbonaceous sulfur hydride material whose identity remains unknown. Herein, first-principles calculations are performed to provide a chemical basis for structural candidates derived by doping H3S with low levels of carbon. Pressure stabilizes unusual bonding configurations about the carbon atoms, which can be six-fold coordinated as CH6 entities within the cubic H3S framework, or four-fold coordinated as methane intercalated into the H-S lattice, with or without an additional hydrogen in the framework. The doping breaks degenerate bands, lowering the density of states at the Fermi level (NF), and localizing electrons in C-H bonds. Low levels of CH4 doping do not increase NF to values as high as those calculated for $$Im\bar{3}m$$

I m

3

¯

m

-H3S, but they can yield a larger logarithmic average phonon frequency, and an electron–phonon coupling parameter comparable to that of R3m-H3S. The implications of carbon doping on the superconducting properties are discussed.