查看更多>>摘要：Superconductivity(SC)was experimentally observed for the first time in antimony polyhydride.The diamond anvil cell combined with a laser heating system was used to synthesize the antimony polyhydride sample at high pressure and high temperature.In-situ high pressure transport measurements as a function of temperature with an applied magnetic field were performed to study the SC properties.It was found that the antimony polyhydride samples show superconducting transition with critical temperature Tc 116 K at 184 GPa.The investigation of SC at magnetic field revealed the superconducting coherent length of～40 Å based on the Ginzburg Landau(GL)equation.Antimony polyhydride superconductor has the second highest Tc in addition to sulfur hydride among the polyhydrides of elements from main groups ⅢA to ⅦA in the periodic table.
查看更多>>摘要：The recent report of room-temperature superconductivity at near-ambient pressure in nitrogen-doped lutetium hydride(Lu-H-N)by Dasenbrock-Gammon et al.[Nature 615,244-250(2023)]has attracted tremendous attention due to its anticipated great impact on technology.However,the results could not be independently reproduced by other groups worldwide in follow-up studies,which elicited intense controversy.Here,we develop a reliable experimental protocol to minimize the extensively concerned extrinsic influences on the sample by starting the reaction from pure lutetium loaded with an H2/N2 gas mixture in a diamond anvil cell under different pressures and temperatures and simultaneously monitoring the entire chemical reaction process using in situ four-probe resistance measurements.Therefore,we could repeatedly reproduce the near-room temperature upsurge of electrical resistance at a relatively early stage of the chemical reaction.However,the mechanism is suggested to be a metal-to-semiconductor/insulator transition associated with the structural modulation in the non-stoichiometric Lu-H-N,rather than superconductivity.
查看更多>>摘要：Room-temperature superconductivity has been a long-held dream of mankind and a focus of considerable interest in the research field of superconductivity.Significant progress has recently been achieved in hydrogen-based superconductors found in superhydrides(hydrides with unexpectedly high hydrogen contents)that are stabilized under high-pressure conditions and are not capturable at ambient conditions.Of particular interest is the discovery of a class of best-ever-known superconductors in clathrate metal superhydrides that hold the record for high superconductivity(e.g.Tc=250-260 K for LaH10)among known superconductors and have great promise to be those that realize the long-sought room-temperature superconductivity.In these peculiar clathrate superhydrides,hydrogen forms unusual'clathrate'cages containing encaged metal atoms,of which such a kind was first reported in a calcium hexa-superhydride(CaH6)showing a measured high Tc of 215 K under a pressure of 170 GPa.In this review,we aim to offer an overview of the current status of research progress on the clathrate metal superhydride superconductors,discuss the superconducting mechanism and highlight the key features(e.g.structure motifs,bonding features,electronic structure,etc.)that govern the high-temperature superconductivity.Future research direction along this line to find room-temperature superconductors will be discussed.
查看更多>>摘要：Since the discovery of the high-temperature superconductors H3S and LaH1o under high pressure,compressed hydrides have received extensive attention as promising candidates for room-temperature superconductors.As a result of current high-pressure theoretical and experimental studies,it is now known that almost all the binary hydrides with a high superconducting transition temperature(Tc)require extremely high pressure to remain stable,hindering any practical application.In order to further lower the stable pressure and improve superconductivity,researchers have started exploring ternary hydrides and had many achievements in recent years.Here,we discuss recent progress in ternary hydrides,aiming to deepen the understanding of the key factors regulating the structural stability and superconductivity of ternary hydrides,such as structural motifs,bonding features,electronic structures,electron-phonon coupling,etc.Furthermore,the current issues and challenges of superconducting ternary hydrides are presented,together with the prospects and opportunities for future research.
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