In 2015, the discovery of superconductivity at 200 K in the high-pressure sulfur hydride H₃S [1] led to a surge in theoretical and experimental research in the field of polyhydrides. After the discovery of superconductivity in LaH₁₀ (T_c = 250 K [2,3]) in 2018, it was expected that room-temperature superconductivity would be found very soon. However, despite the past 5 years, this has not happened. But in 2024-2025, things seem to be changing, and further progress toward the room-temperature superconductivity is becoming increasingly clear.

In my report, I will focus on recent studies of the superconducting properties of lanthanum polyhydrides and ternary La-Sc-H system under high pressure above 1 Mbar. We will review early work from 2018-2019 on resistivity measurements in lanthanum hydrides that revealed superconductivity at and above 260 K [2]. We will then move on to a recent paper by scientists from the IOP CAS who discovered a previously unknown resistive transition at 265 K [4]. Finally, I will show our own high-frequency proton NMR measurements in lanthanum hydride LaH₁₂, confirming the emergence of superconductivity around 267-280 K in the La-H system [5]. Our resistive and radio-frequency studies of the La-Sc-H system confirm the findings of superconductivity at temperatures from 0 to +6 ^oC [6]. Thus, a growing number of studies indicate that room-temperature superconductivity has already been achieved in compressed metal superhydrides. But final proof and verification will probably take the next few years.

References:

[1]        A. P. Drozdov et al. Nature 525, 73 (2015).

[2]        M. Somayazulu et al., Phys. Rev. Lett. 122, 027001 (2019).

[3]        A. P. Drozdov et al., Nature 569, 528 (2019).

[4]        Y. L. Wu et al., Nature Communications 15, 9683 (2024).

[5]        D. V. Semenok et al. arXiv:2412.11727  (2024).

[6]        D. V. Semenok et al. arXiv:2408.07477  (2024).