The discovery of superconductivity at 200 kelvin in the hydrogen sulfide system at high pressures¹ demonstrated the potential of hydrogen-rich materials as high-temperature superconductors. Recent theoretical predictions of rare-earth hydrides with hydrogen cages^2,3 and the subsequent synthesis of LaH₁₀ with a superconducting critical temperature (T_c) of 250 kelvin^4,5 have placed these materials on the verge of achieving the long-standing goal of room-temperature superconductivity. Electrical and X-ray diffraction measurements have revealed a weakly pressure-dependent T_c for LaH₁₀ between 137 and 218 gigapascals in a structure that has a face-centred cubic arrangement of lanthanum atoms⁵. Here we show that quantum atomic fluctuations stabilize a highly symmetrical \({Fm}\overline{3}{m}\) crystal structure over this pressure range. The structure is consistent with experimental findings and has a very large electron–phonon coupling constant of 3.5. Although ab initio classical calculations predict that this \({Fm}\overline{3}{m}\) structure undergoes distortion at pressures below 230 gigapascals^2,3, yielding a complex energy landscape, the inclusion of quantum effects suggests that it is the true ground-state structure. The agreement between the calculated and experimental T_c values further indicates that this phase is responsible for the superconductivity observed at 250 kelvin. The relevance of quantum fluctuations calls into question many of the crystal structure predictions that have been made for hydrides within a classical approach and that currently guide the experimental quest for room-temperature superconductivity^6,7,8. Furthermore, we find that quantum effects are crucial for the stabilization of solids with high electron–phonon coupling constants that could otherwise be destabilized by the large electron–phonon interaction⁹, thus reducing the pressures required for their synthesis.

在高压硫化氢系统中发现 200 开尔文的超导性¹证明了富氢材料作为高温超导体的潜力。^{最近对具有氢笼2,3}的稀土氢化物的理论预测以及随后超导临界温度 ( T _c ) 为 250 开尔文^{4,5的 LaH} ₁₀的合成使这些材料接近于实现长期目标室温超导性。电学和 X 射线衍射测量揭示了LaH _{10的弱压力依赖性}Tc^{在具有镧原子5}的面心立方排列的结构中介于 137 和 218 吉帕之间。在这里，我们表明量子原子涨落在这个压力范围内稳定了高度对称的\({Fm}\overline{3}{m}\)晶体结构。该结构与实验结果一致，具有非常大的电子-声子耦合常数 3.5。尽管从头算经典计算预测此\({Fm}\overline{3}{m}\)结构在低于 230 吉帕^2,3的压力下会发生变形，产生复杂的能量景观，但包含量子效应表明它是真正的基态结构。计算的和实验的T _{c之间的一致性}值进一步表明该相是造成在 250 开尔文观察到的超导性的原因。量子涨落的相关性对许多在经典方法中对氢化物所做的晶体结构预测提出了质疑，这些预测目前指导着对室温超导性的实验探索^6,7,8。此外，我们发现量子效应对于稳定具有高电子-声子耦合常数的固体至关重要，否则这些固体可能会因大的电子-声子相互作用⁹而不稳定，从而降低了它们合成所需的压力。