Origin of the near-room temperature resistance transition in lutetium with H2/N2 gas mixture under high pressure

Abstract

The recent report of room-temperature superconductivity at near-ambient pressure in nitrogen-doped lutetium hydride (Lu-H-N) by Dasenbrock-Gammon et al. [Nature 615, 244-250 (2023)] has attracted tremendous attention due to its anticipated great impact on technology. However, the results could not be independently reproduced by other groups worldwide in follow-up studies, which excited intense controversy. Here, we develop a reliable experimental protocol to minimize the extensively concerned extrinsic influences on the sample by starting the reaction from pure lutetium loaded with H2/N2 gas mixture in a diamond anvil cell under different pressures and temperatures and simultaneously monitoring the entire chemical reaction process using in situ four-probe resistance measurements. Therefore, we could repeatedly reproduce the near-room temperature upsurge of electrical resistance at the relatively early stage of the chemical reaction. However, the mechanism is suggested to be a metal-to-semiconductor/insulator transition associated with the structural modulation in the non-stoichiometric Lu-H-N, rather than superconductivity.

The preface: Toward higher-Tc superconductivity under lower pressure—from binary to ternary superhydrides

“…The second research article authored by D. Peng et al. [ 9 ] concerns the nature of the near-room-temperature resistance transition in lutetium with H 2 /N 2 gas mixture under pressure. With a comprehensive in-depth study, the authors could repeatedly reproduce the near-room-temperature upsurge of electrical resistance in the Lu–H–N system, but the ostensive ‘superconductivity’ is actually a metal-to-semiconductor transition.…”