Superconductivity is not restricted to low temperatures! Indeed, transition temperatures up to 260 K have been demonstrated by multiple groups in H3S, LaH10, YH9, at very high pressures [1–3]. This is a success story of both theory and experiment. Theory has mastered significant predictions of new superconductors and has been crucial to guide experimental efforts. Experiments have mastered many technical challenges. Together, these efforts open pathways to realise higher transition temperature at low pressures in the future.
We present studies of hydride superconductors, where high-energy lattice phonons couple to hydrogen orbitals in structures stabilised at very high pressures only. We have developed methods for in situ synthesis and characterise structure and electronic properties of hydrides in diamond-anvil pressures cells at megabar pressures. We show that H3S harbours clean-limit superconductivity. We present our discovery of the new high-temperature superconductor La4H23 [4] and demonstrate superconductivity in thin films of LaH10 with a Tc=250 K consistent with bulk LaH10 [2,5]. We discuss stability of hydrides and their superconductivity [6].

[1] Kong, P. et al. Nature Communications 12, 5075 (2021).
[2] Somayazulu, M. et al. Phys. Rev. Lett. 122, 027001 (2019).
[3] Drozdov, A. P. et al. Nature 525, 73 (2015).
[4] Cross, S. et al. Phys. Rev. B 109, L020503 (2024).
[5] Drozdov, A. P. et al. Nature 569, 528–531 (2019).
[6] Zhou, Y. et al. Nature Communications 16, 1135 (2025).