High-temperature superconductivity in sulfur hydride evidenced by alternating-current magnetic susceptibility.

Hongyu Yu,Yanping Huang,Bertil Sundqvist,Xin Li,Qiang Zhou,Defang Duan,Xiaoli Huang,Tian Cui,Bingbing Liu,Fangfei Li,Xin Wang

doi:10.1093/nsr/nwz061

Abstract

ABSTRACTThe search for high-temperature superconductivity is one of the research frontiers in physics. In the sulfur hydride system, an extremely high Tc (∼200 K) has been recently developed at pressure. However, the Meissner effect measurement above megabar pressures is still a great challenge. Here, we report the superconductivity identification of sulfur hydride at pressure, employing an in situ alternating-current magnetic susceptibility technique. We determine the superconducting phase diagram, finding that superconductivity suddenly appears at 117 GPa and Tc reaches 183 K at 149 GPa before decreasing monotonically with increasing pressure. By means of theoretical calculations, we elucidate the variation of Tc in the low-pressure region in terms of the changing stoichiometry of sulfur hydride and the further decrease in Tc owing to a drop in the electron–phonon interaction parameter λ. This work provides a new insight into clarifying superconducting phenomena and anchoring the superconducting phase diagram in the hydrides.

Highlights

Since the discovery of superconductivity slightly more than a century ago [1], the quest for everhigher critical temperatures, Tc, has remained a great challenge and an important topic for both experimental and theoretical research
We report measurements of the Meissner effect under variable pressure to map the superconducting diamagnetism and high-temperature superconducting state in the sulfur hydride system, using a highly sensitive magnetic susceptibility technique adapted for a megabar-pressure diamond anvil cell (DAC)
The alternating-current susceptibility was detected with a lock-in amplifier (LIA)

Summary

INTRODUCTION

Since the discovery of superconductivity slightly more than a century ago [1], the quest for everhigher critical temperatures, Tc, has remained a great challenge and an important topic for both experimental and theoretical research. Because of their high Debye temperatures and chemical precompression, some hydrides have been predicted theoretically as good candidates to realize hightemperature superconductivity at pressures lower than those expected for metallic hydrogen [2,3,4,5,6]. A novel method, in which the magnetic field on a Sn sensor inside the H2S sample was monitored by nuclear resonance scattering of synchrotron radiation, was

GPa and 200 K

RESULTS AND DISCUSSION

CONCLUSION