James C. McGroddy Prize for New Materials (2020): Progress in high-temperature conventional superconductivity
Invited
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 GPa1, 243 K at 200 GPa in YH92, 250-260 K in LaH103,4, and 287 K in carbonaceous hydrogen sulfide5. 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 hydrogen6. The second structure realized in H3S1 is different: here 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 discuss different ways for further increase of Tc at high and ambient pressures.
1 Drozdov, A. P., Eremets, M. I., Troyan, I. A., Ksenofontov, V. & Shylin, S. I. Conventional superconductivity at 203 K at high pressures. Nature 525, 73 (2015).
2 Kong, P. P. et al. Superconductivity up to 243 K in yttrium hydrides under high pressure. arXiv:1909.10482 (2019).
3 Drozdov, A. P. et al. Superconductivity at 250 K in lanthanum hydride under high pressures Nature 569 528 (2019).
4 Somayazulu, M. et al. Evidence for Superconductivity above 260 K in Lanthanum Superhydride at Megabar Pressures. Phys. Rev. Lett. 122 027001 (2019).
5 Snider, E. et al. Room-temperature superconductivity in a carbonaceous sulfur hydride. Nature (2020).
6 Ashcroft, N. W. Metallic hydrogen: A high-temperature superconductor? Phys. Rev. Lett. 21, 1748-1750 (1968).
1 Drozdov, A. P., Eremets, M. I., Troyan, I. A., Ksenofontov, V. & Shylin, S. I. Conventional superconductivity at 203 K at high pressures. Nature 525, 73 (2015).
2 Kong, P. P. et al. Superconductivity up to 243 K in yttrium hydrides under high pressure. arXiv:1909.10482 (2019).
3 Drozdov, A. P. et al. Superconductivity at 250 K in lanthanum hydride under high pressures Nature 569 528 (2019).
4 Somayazulu, M. et al. Evidence for Superconductivity above 260 K in Lanthanum Superhydride at Megabar Pressures. Phys. Rev. Lett. 122 027001 (2019).
5 Snider, E. et al. Room-temperature superconductivity in a carbonaceous sulfur hydride. Nature (2020).
6 Ashcroft, N. W. Metallic hydrogen: A high-temperature superconductor? Phys. Rev. Lett. 21, 1748-1750 (1968).
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Presenters
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Mikhail Eremets
Max-Planck Institut für Chemie, Max-Planck-Institut fur Chemie, Hahn-Meitner Weg 1, 55128 Mainz, Germany
Authors
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Mikhail Eremets
Max-Planck Institut für Chemie, Max-Planck-Institut fur Chemie, Hahn-Meitner Weg 1, 55128 Mainz, Germany