Superconductivity temperature record broken due to rotten egg smell For nearly three decades, the search for room-temperature superconductors has focused on exotic materials called cuprates, which can carry currents without losing energy as heat at temperatures as low as -109 degrees Celsius. However, scientists claim to have repeated this record using a hydrogen sulfide molecule. When they subjected a tiny sample of this material to pressures similar to those found in the Earth's core, it became superconducting at -83 degrees Celsius. "If the result is replicated, it will be a historic discovery," says Robert Cava, a solid-state chemist at Princeton University. According to the established theory of superconductivity, called the BCS theory after its creators, John Bardeen, Leon Cooper and Robert Schrieffer, vibrations in the atoms of a crystal can cause electrons to form “Cooper pairs” that can flow through the crystal without resistance. The BCS theory was developed in the 1950s, but many physicists believe it cannot explain superconductivity in cuprates, which were discovered in 1986, or in iron pnictides, discovered in 2006. Scientists believe that the BCS theory could lead to the discovery of other types of superconductors that operate at high temperatures, especially in materials containing light elements such as hydrogen. They create more frequent vibrations, forming stronger bonds between electron pairs. The latest research builds on the work of Neil Ashcroft, a physicist at Cornell University in Ithaca, New York, who has studied the superconducting potential of hydrogen compounds. More specifically, he examined a recent theoretical prediction by a group of Chinese physicists who suggested that hydrogen sulfide should be superconducting at temperatures on the order of -100 degrees Celsius and at pressures of 1.6 million atmospheres. This pressure compresses electrons into Cooper pairs and makes them more resistant to thermal fluctuations. Mikhail Eremets and his colleagues at the Max Planck Institute for Chemistry in Mainz, Germany, placed a sample of hydrogen sulfide one-hundredth of a millimeter across between two diamond anvils, and then used electrodes to measure how the electrical resistance of the material changed as the system cooled to near absolute zero. Scientists discovered that at a pressure of 1.8 million atmospheres and a temperature of -109 degrees Celsius, the resistance suddenly dropped, indicating a transition to superconductivity. Scientists attribute this unexpected critical temperature to the fact that hydrogen sulfide molecules contain a relatively large number of hydrogen atoms. These molecules, scientists say, should remain superconducting at this temperature. Scientists also provide several evidence that they saw a lower transition temperature (about -183 degrees Celsius) when they replaced heavy sulfur deuteride with sulfur hydride. The heavier the atoms, the more the crystalline vibrations slow down and the worse superconductivity appears. The scientists' work was published on arXiv.oarxiv.orgly December. If the result of the work is confirmed by other groups, there will be a significant increase in the critical temperature required to achieve superconductivity. The current record (magnesium diboride) is set at -234 degrees Celsius. Physicists who have read the work write that the results of Eremets and his colleagues literally created a stir in the scientific community, and there are no complaints about the paper conclusions yet. Alexander Gurevich, a theorist at Old Dominion University in Norfolk, agrees that the results will mean “a significant breakthrough in the study of superconductivity,” but is very cautious in his statements. He says the authors still need to demonstrate the so-called Meissner effect, in which the material "pushes out" magnetic field lines as it cools to a superconducting state. The physicist also expresses hope that other scientists will quickly reproduce the researchers’ experiments. The discovery by Eremets and his colleagues suggests th yt3.ggpht