High-temperature superconductivity of Pm3¯n Lu4H23 immersed in an as-synthesized lutetium polyhydride

Abstract

The precompression effect of foreign elements affords a promising route to metallizing hydrogen atoms under moderate pressure and achieving superconductivity with high transition temperature (TC) in polyhydrides. Recently, lutetium (Lu) polyhydrides are receiving considerable attention due to their fully filled f orbitals, which are favorable for realizing high TC. The highest TC observed in the as-synthesized lutetium polyhydrides up to now has reached 65–71 K under pressures of 181–218 GPa, which was attributed to the Pm3¯n Lu4H23 phase but without computational analysis. Here we perform first-principles calculations on the bonding feature, the stability, the electronic property, and the superconductivity of Lu4H23. Lu4H23 presents robust metallicity due to the orbital hybridizations associated with the H-H covalent and Lu-H ionic bonds, as well as the charge transfer from Lu to H atoms. Our calculations reveal that Lu4H23 can be stabilized at pressures above ∼200 GPa, whose TC is estimated to be 69–225 (103–210) K at 200 (218) GPa and maintains at the average values around 150–200 K under the pressures exceeding 250 GPa. We propose that the Fm3¯m LuH plays a possible role in stabilizing Lu4H23 at pressures lower than 200 GPa, and, simultaneously, decreases the TC of superconductivity in the as-synthesized lutetium polyhydrides. Our work provides a computational analysis on Lu4H23, and the predicted high TC is expected to be experimentally realized by increasing pressure and optimizing synthesis process to eliminate the LuH phase.

Source-reported materials — not catalogue approval

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