Effect of pressure, nitrogen-doping, and lanthanide elements substitution on the superconductivity of rocksalt-type LuH

• Published in: Journal of applied physics 2024-07, Vol.136 (2)
• Main Authors: Jiang, Kai-Yue, Chen, Ying-Jie, Lu, Hong-Yan
• Format: Article
• Language: English
• Subjects: Density functional theory; Hydrides; Lutetium; Nitrogen; Phonons; Pressure effects; Substitutes; Superconductivity
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/5.0215212

The report on near-ambient superconductivity in nitrogen-doped lutetium hydride is still under controversy. Here, guided by x-ray diffraction data of nitrogen-doped lutetium hydride, we choose a possible cubic superconducting phase named rocksalt-type LuH (RS-LuH) and study the superconductivity of pristine RS-LuH, nitrogen-doped RS-LuH named Lu 4NH 3, and lanthanide elements substitution of RS-LuH at pressures 0, 1, and 10 GPa by performing density functional theory and isotropic Eliashberg equation. As pressure increases from 0 to 10 GPa, all phonon spectra notably harden, resulting in the suppression of electron–phonon coupling. Moreover, the decrease in superconducting critical temperature ( T c) of Lu 4NH 3 is due to the reduction of electron–phonon coupling and the density of states at the Fermi level compared with pristine RS-LuH. Finally, our investigation reveals a monotonic increase in T c with ascending atomic numbers via lanthanide element substitution. Notably, RS-LuH exhibits the highest T c ( T c = 19.7 K) among all compounds we studied. Therefore, our theoretical exploration enriches the understanding of the superconductivity in nitrogen-doped lutetium hydride under varying pressures.