Prof. Russell Hemley

Abstract:

Superconductivity in the vicinity of room temperature has the potential to revolutionize numerous technologies and sustainability as well as our understanding of condensed matter. Zero electrical resistance and expulsion of magnetic field below a critical temperature are critical tests of superconductivity. As for the original high-T_c cuprate superconductors, accurate crystal structures are also required for complete characterization of the materials [1]. Inspired by theoretical predictions for hydrogen-rich materials under pressure [2], previous work from our group has established the existence of near-room temperature superconductivity at megabar pressures [3], now reproduced by numerous other groups [4]. Recently reported evidence for superconductivity at ambient P-T conditions in nitrogen-doped lutetium hydride (Lu-N-H) has been promising but controversial [5]. Our group has conducted independent electrical resistivity and magnetic susceptibility measurements on the material that confirm the remarkable properties of the material as well as the difficulty of synthesis [6]. First-principles DFT and DFT+U calculations provide important insights into the behavior of this remarkable class of materials [7]. There are prospects for similar high T_c superconductivity in related compounds, including complex quaternary and higher order chemical systems.