Observation of Conventional Near Room Temperature Superconductivity in Carbonaceous Sulfur Hydride

Hiranya Pasan; Elliot Snider; Sasanka Munasinghe; Sachith E. Dissanayake; Nilesh P. Salke; Muhtar Ahart; Nugzari Khalvashi-Sutter; Nathan Dasenbrock-Gammon; Raymond McBride; G. Alexander Smith; Faraz Mostafaeipour; Dean Smith; Sergio Villa Cortés; Yuming Xiao; Curtis Kenney-Benson; Changyong Park; Vitali Prakapenka; Stella Chariton; Keith V. Lawler; Maddury Somayazulu; Zhenxian Liu; Russell J. Hemley; Ashkan Salamat; Ranga P. Dias

arXiv · 2302.08622

Observation of Conventional Near Room Temperature Superconductivity in Carbonaceous Sulfur Hydride

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Abstract

The phenomenon of high temperature superconductivity, approaching room temperature, has been realized in a number of hydrogen-dominant alloy systems under high pressure conditions1-12. A significant discovery in reaching room temperature superconductivity is the photo-induced reaction of sulfur, hydrogen, and carbon that initially forms of van der Waals solids at sub-megabar pressures. Carbonaceous sulfur hydride has been demonstrated to be tunable with respect to carbon content, leading to different superconducting final states with different structural symmetries. A modulated AC susceptibility technique adapted for a diamond anvil cell confirms a Tc of 260 kelvin at 133 GPa in carbonaceous sulfur hydride. Furthermore, direct synchrotron infrared reflectivity measurements on the same sample under the same conditions reveal a superconducting gap of ~85 meV at 100 K in close agreement to the expected value from Bardeen-Cooper-Schrieffer (BCS) theory13-18. Additionally, x-ray diffraction in tandem with AC magnetic susceptibility measurements above and below the superconducting transition temperature, and as a function of pressure at 107-133 GPa, reveal the Pnma structure of the material is responsible for the close to room-temperature superconductivity at these pressures.

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Hiranya Pasan, Elliot Snider, Sasanka Munasinghe, Sachith E. Dissanayake, Nilesh P. Salke, Muhtar Ahart, Nugzari Khalvashi-Sutter, Nathan Dasenbrock-Gammon, Raymond McBride, G. Alexander Smith, Faraz Mostafaeipour, Dean Smith, Sergio Villa Cortés, Yuming Xiao, Curtis Kenney-Benson, Changyong Park, Vitali Prakapenka, Stella Chariton, Keith V. Lawler, Maddury Somayazulu, Zhenxian Liu, Russell J. Hemley, Ashkan Salamat, Ranga P. Dias. 2023-02-16. Observation of Conventional Near Room Temperature Superconductivity in Carbonaceous Sulfur Hydride. https://arxiv.org/abs/2302.08622

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