Hydrogen sulfide — the compound responsible for the smell of rotten eggs — conducts electricity with zero resistance at a record high temperature of 203 kelvin (–70 °C), reports a paper published in Nature.
The results of the work, which represents a historic step towards finding a room-temperature superconductor, were released on the arXiv preprint server in December and followed up by more in June. They have already sparked a wave of excitement within the research community.
According to December result,
“Scientists say that they have trumped that record using the common molecule hydrogen sulphide. When they subjected a tiny sample of that material to pressures close to those inside Earth’s core, the researchers say that it was superconductive at 190 K (–83 ˚C).”
According to June result,
“The long-standing quest to find a material that can conduct electricity without resistance at room temperature may have taken a decisive step forward. Scientists in Germany have observed the common molecule hydrogen sulfide superconducting at a record-breaking 203 kelvin (–70 ˚C) when subjected to very high pressures.”
A superconductor that works at room-temperature would make everyday electricity generation and transmission vastly more efficient, as well as giving a massive boost to current uses of superconductivity such as the enormous magnets used in medical imaging machines.
Researchers find that when they subject samples of hydrogen sulfide to extremely high pressures — around 1.5 million atmospheres (150 gigapascals) — and cool them below 203 K, the samples display the classic hallmarks of superconductivity: zero electrical resistance and a phenomenon known as the Meissner effect. The Meissner effect occurs when a superconducting material is placed in an external magnetic field and there is no field inside the sample, unlike in normal materials.
According to Christoph Heil of the Graz University of Technology in Austria, other scientists are intensely interested in the result because it was achieved without using exotic materials such as the copper-containing compounds called ‘cuprates’ which until now have held the record for the highest superconducting temperature (133 K (–140 °C) at ambient pressure and 164 K (–109 °C) at high pressure). He says that the pressurized hydrogen sulfide seems to be a ‘conventional’ superconductor in which vibrations within the material’s crystal lattice drive electrons to form ‘Cooper pairs’ that can flow through the crystal without resistance.
According to research paper, “A superconductor is a material that can conduct electricity without resistance below a superconducting transition temperature. The highest temperature that has been achieved to date is in the copper oxide system: 133 kelvin at ambient pressure and 164 kelvin at high pressures. As the nature of superconductivity in these materials is still not fully understood (they are not conventional superconductors), the prospects for achieving still higher transition temperatures by this route are not clear”
In calculations reported in April, researchers at the Pierre and Marie Curie University in Paris found that this hydrogen sulfide results could be explained using a modified version of the conventional theory of low-temperature superconductivity based on lattice vibrations. That is surprising because many scientists assumed that superconductivity at temperatures of more than a few tens of Kelvin required exotic materials that do not exhibit conventional superconductivity.
“For others, such theoretical analyses are superfluous until the result by Eremets and co-workers is confirmed experimentally by independent teams. Several are working towards that goal, including Katsuya Shimizu of Osaka University in Japan and colleagues, who have seen the loss of resistance in pressurized hydrogen sulfide, but have yet to observe the Meissner effect. Meanwhile, four other groups contacted by Nature‘s news team — three in China and one in the United States — have yet to confirm either the electrical or magnetic effects.”
Read below the discussion on reddit about “Superconductivity recorded at a record high temperature of 203K (-70°C). Hydrogen Sulfide was able to conduct electricity with zero resistance at this temperature”
“The catch here is that it only works in a diamond anvil at millions of atmospheres of pressure. This is still progress in the general direction of hovercars, machinery with no parts that touch and wear, cheap energy storage and technology with futuristic floaty bits.””Presently temperature control is cheaper. Alternatives are primarily being looked for due to the relative cost/scarcity of liquid helium. Unfortunately to get to liquid nitrogen temperatures, current technology superconductors are ceramics. Unfortunately they tend not to hold up well under the stresses of medical and scientific applications too well.”
“According to the article, the previous record was 133 K (-140 C).”
“Heat in electronics is generated because of their electrical resistance, so a system built from superconductive material (which has no resistance) would not get hot during operation.”
“In a home computer, limiting factor is usually clock speed and the distance the signal needs to travel in the circuit. An electrical signal goes at about 30 cm/ns, it needs to complete the distance it has to travel in the circuit before the end of the cycle which for today’s computers is typically less than a ns at a few hundred ps (picoseconds). Clocks can run faster at lower Temps however and heat does degrade the performance.”
“There are quite a few compounds that are detectable at ppb (parts per billion) levels, many of them are either amines (containing nitrogen) or sulphuric. These are precisely the sort of chemicals that are released by rotting organic matter, so the evolutionary advantage of being able to detect those is pretty obvious.”