Room-temperature superconductivity in boron- and nitrogen-doped lanthanum superhydride

Abstract

Recent theoretical and experimental studies of hydrogen-rich materials at megabar pressures (i.e., >100 GPa) have led to the discovery of very high-temperature superconductivity in these materials. Lanthanum superhydride LaH10 has been of particular focus as the first material to exhibit a superconducting critical temperature (Tc) near room temperature. Experiments indicate that the use of ammonia borane as the hydrogen source can increase the conductivity onset temperatures of lanthanum superhydride to as high as 290 K. Here we examine the doping effects of B and N atoms on the superconductivity of LaH10 in its fcc (Fm3¯m) clathrate structure at megabar pressures. Doping at H atomic positions strengthens the H32 cages of the structure to give higher phonon frequencies that enhance the Debye frequency and thus the calculated Tc. The predicted Tc can reach 288 K in LaH9.985N0.015 within the average high-symmetry structure at 240 GPa. The remarkably large shift in Tc to higher values produced by small degrees of chemical doping opens the prospect for the creation of still higher-temperature superconductivity in superhydrides potentially at even lower-pressure conditions.

Source-reported materials — not catalogue approval

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