Prof. M. Eremets [Max-Planck-Institut fur Chemie, Germany
Title: Recent Progress in High Temperature Conventional Superconductivity
Language: English presentation
Time: 14:00 - 15:30 PM, Tuesday, June 14th, 2022
Place: Tencent Meeting ID: 749-862-666
Host: Thomas Meier
Abstract
Room-temperature superconductivity became realistic as a result of dramatic progress in conventional superconductivity: starting from the critical temperature Tc =203 K in hydrogen sulfide under high pressures of about 150 GPa [1], 243 K at 200 GPa in YH9 [2], 250-260 K in LaH10 [3-6], Two main structures of the superconducting hydrides were discovered. In the first family, a cage-like structure is realized. In particular, in lanthanum hydride LaH10, La atom is located at the center of the cage of hydrogen atoms. The lanthanum atom acts as an electron donor contributing to electron pairing, while the hydrogen atoms form weak covalent bonds with each other within the cage. This and other superhydrides (YH9, CaH6) can be considered as a close realization of superconductng metallic hydrogen. In the second structure realized in H3S [1] each hydrogen atom is connected by a strong covalent bond to the two nearby sulfur atoms. The strong bonding provides large electron-phonon coupling and enhanced superconductivity. The covalent metals are perspective ambient pressure superconductors. We will emphasize our recent dramatic development of studies of magnetic properties of the superconductors.
1. Drozdov, A.P., et al., Conventional superconductivity at 203 K at high pressures. Nature 2015. 525: p. 73.
2. Kong, P.P., et al., Superconductivity up to 243 K in the yttrium-hydrogen system under high pressure. Nature Comm., 2021. 12: p. 5075.
3. Drozdov, A.P., et al., Superconductivity at 250 K in lanthanum hydride under high pressures Nature, 2019. 569 p. 528.
4. Somayazulu, M., et al., Evidence for Superconductivity above 260 K in Lanthanum Superhydride at Megabar Pressures. Phys. Rev. Lett., 2019. 122 p. 027001.
5. Sun, D., et al., High-temperature superconductivity on the verge of a structural instability in lanthanum superhydride. Nature Communications, 2021.
6. Minkov, V., et al., Experiments on superconductivity in S-C-H system at high pressure. Raman. X-ray and electrical studies. 2021.
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