Hydrogen Vacancy Induced Superconductivity Collapse in A15 Lanthanum Hydride
Year: 2025
Type: article
Abstract: Hydrogen-rich lanthanum compounds show the highest known superconducting transition temperatures at high pressure. Despite the pivotal role of hydrogen within these systems, there has been no systematic exploration of how the composition and superconducting properties are intertwined. Our experimental and computational studies demonstrate that A15-type LaH_{5.75-x} hosts high-T_{c} superconductivity (T_{c}=98 K at 94 GPa) when available interstitial sites are fully occupied with hydrogen. Upon decompression, a site-selective hydrogen depopulation drives a superconductor-to-insulator transition with a threshold composition of LaH_{5}. Strikingly, the A15 framework is experimentally retained from 120 to 4 GPa, with reversible pressure-dependent hydrogen content changes from LaH_{5.75} down to LaH_{3.25}. Our results demonstrate the exceptional stability and tunability of the A15 framework, offering a unique platform to probe the interplay between composition, structure, and superconductivity in hydrogen-rich materials.
Source: Physical Review Letters
DOI: 10.1103/8b43-4dvw
Authors: Israel Osmond, Lewis J. Conway, Mikhail A. Kuzovnikov, Callum Stevens, Tomas Marqueño, Hannah A. Shuttleworth, Andrew Huxley, Chris J. Pickard, Graeme J. Ackland, Ross T. Howie, Miriam Peña-Alvarez
Language: English
Subfield: Geophysics
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,750
OpenAlex ID: W4417465642