Towards room-temperature superconductivity: Experimental evidence. -(Vasily S. Minkov/ LNCMI / Seminar). – 4/11/2026, 14H

Seminar LNCMI

Vasily S. Minkov, Max Planck Institute for Chemistry (Germany)

Seminar LNCMI, 4/11/2026, 14H, LNCMI, Toulouse

Abstract
Superconductivity – the complete loss of electrical resistance and the expulsion of magnetic flux – is one of the most remarkable phenomena in condensed matter physics. Following its discovery in mercury in 1911, it was long regarded as phenomenon confined to very low temperatures. The Bardeen–Cooper–Schrieffer theory, together with subsequent theoretical advances, demonstrated that there is no fundamental upper limit to the superconducting critical temperature (Tc), implying that room-temperature superconductivity is, in principle, achievable.

A major breakthrough came in 2015 with the pioneering work of Mikhail Eremets and collaborators, who discovered superconductivity with a then-record Tc of 203 K in H3S, formed by compressing hydrogen sulfide (H2S) to approximately 150 GPa. This result provided the first experimental confirmation of high-Tc conventional superconductivity in hydrides and sparked intense theoretical and experimental activity in the field.

Subsequent studies identified other metal hydrides – notably the so-called superhydrides LaH10 and YH9 – with Tc values approaching 250 K, bringing the field closer than ever to room-temperature superconductivity. More recently, attention has shifted from binary to ternary hydrides, which offer additional chemical degrees of freedom and the potential for even higher Tc values, but also pose greater challenges for synthesis and characterization.

Despite formidable experimental constraints – including the synthesis and characterization of micrometer-scale samples in diamond anvil cells at multimegabar pressures – superconductivity in these compounds has been confirmed by multiple complementary techniques. Four-probe electrical transport measurements remain the benchmark for detecting resistive transitions, while advanced magnetic probes such as SQUID magnetometry, nuclear resonant scattering, double-modulation AC susceptibility, and nitrogen-vacancy center magnetometry enable direct detection of magnetic-field screening, flux expulsion, and flux trapping. Most recently, electron tunneling spectroscopy has been extended to megabar pressures, providing direct spectroscopic evidence of the superconducting gap in hydrogen-rich materials.

In this talk, I will review the development of conventional high-temperature superconductivity in hydrides, with particular emphasis on the latest results from our group. I will also present our recent experimental progress in the search for room-temperature superconductors, including the development of new measurement techniques for extreme-pressure environments and emerging indications of “hot” superconductivity in carbon-based materials.