摘要
Recently,room-temperature superconductivity has been reported in a nitrogen-doped lutetium hydride at near-ambient pressure[Dasenbrock-Gammon et al.,Nature 615,244(2023)].The superconducting properties might arise from Fm3m-LuH_(3)−δNε.Here,we systematically study the phase diagram of Lu–N–H at 1 GPa using first-principles calculations,and we do not find any thermodynamically stable ternary compounds.In addition,we calculate the dynamic stability and superconducting properties of N-doped Fm3m-LuH_(3) using the virtual crystal approximation(VCA)and the supercell method.The R3m-Lu_(2)H_(5)N predicted using the supercell method could be dynamically stable at 50 GPa,with a T_(c) of 27 K.According to the VCA method,the highest T_(c) is 22 K,obtained with 1%N-doping at 30 GPa.Moreover,the doping of nitrogen atoms into Fm3m-LuH_(3) slightly enhances T_(c),but raises the dynamically stable pressure.Our theoretical results show that the T_(c) values of N-doped LuH_(3) estimated using the Allen–Dynes-modified McMillan equation are much lower than room temperature.
基金
This work was supported by the National Key R&D Program of China(Grant Nos.2018YFA0305900 and 2022YFA1402304)
the National Natural Science Foundation of China(Grant Nos.12122405,52072188,and 12274169)
the Program for Changjiang Scholars and Innovative Research Team in University(Grant No.IRT_15R23)
a Jilin Provincial Science and Technology Development Project(Grant No.20210509038RQ).Some of the calculations were performed at the High Performance Computing Center of Jilin University and on TianHe-1(A)at the National Supercomputer Center in Tianjin.
