Funct. Mater. 2022; 29 (3): 321-325.

doi:https://doi.org/10.15407/fm29.03.321

On the possibility of "high-temperature" electrical superconductivity of the superhydride Pd(H)n-x

Yu.I.Boyko1, V.V.Bogdanov1, R.V.Vovk1, B.V.Grinyov2

1V.N.Karazin Kharkiv National University, 4 Svobody Sq., 61022 Kharkiv, Ukraine
2Institute of Scintillation Materials, STC "Institute of Single Crystals", National Academy of Sciences of Ukraine, 60 Nauki Ave., 61072 Kharkiv, Ukraine

Abstract: 

Hydrogen is the simplest and at the same time very important and interesting chemical element. Under pressure ~500 GPa hydrogen molecules form a metal phase. According to theory, "metallized" hydrogen is a "high-temperature" superconductor, ie it is characterized by almost zero electrical resistance in the entire temperature range of this phase. Hydrogen compounds with atoms of other elements, for example, with atoms of metals, form a stable metal phase ("hydrides") under the action of much lower pressure ≤100 GPa. At the same time some hydrides (H3S, LaH10 etc.) are superconductors at temperatures T≤200 K. An urgent and very intriguing task for researchers is to identify new substances (including new "metal" hydrides) that are stable at normal (atmospheric) pressure and at the same time have "high-temperature" superconductivity. This paper discusses the possibility of obtaining such a material on the basis of a solid solution of hydrogen in palladium Pd(H)n-x. Palladium metal has two unique physicochemical properties: first, it is able to extremely actively absorb hydrogen (up to ~103 volumes of H2 molecule per volume of Pd atom) and, secondly, in the process of dissolving hydrogen in this metal, dissociation of molecules easily occurs H2. In this case, each electron of the hydrogen atom is combined with the valence electrons of the palladium metal lattice (there is a "collectivization" of electrons), and the H+ nucleus is converted into a proton, ie into a particle with extremely low mass and size. Thus, the "metallization" of the hydride Pd(H)n-x can occur without the action ofadditional external pressure. The analysis carried out in this paper shows that the specific crystal structure of this substance and the features of the energy spectrum of its electronic subsystem, enhance the electron-phonon interaction and, accordingly, determine the possibility of "high-temperature" superconductivity.

Keywords: 
high-temperature superconductivity, palladium hydride, electron-phonon interaction.
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