Study on superconducting Li-Se-H hydrides.

The structures, stabilities and superconducting properties of LiSeH n ( n = 4-10) hydrides at 150-300 GPa were studied by the genetic algorithm (GA) and DFT calculation method. Three stable stoichiometries of LiSeH 4 , LiSeH 6 and LiSeH 10 were uncovered under high pressure. Four other metastable stoichiometries of LiSeH 5 , LiSeH 7 , LiSeH 8 , and LiSeH 9 were also studied. By analyzing the electronic band structure and electronic density of states, C 2 LiSeH 4 , Pmm 2 LiSeH 6 and C 2 LiSeH 10 were all found to be metal phases above 150 GPa. Electron-phonon coupling calculations showed that C 2 LiSeH 4 and Pmm 2 LiSeH 6 were promising superconductors. The predicted T c values of C 2 LiSeH 4 and Pmm 2 LiSeH 6 were 77 K at 200 GPa and 111 K at 250 GPa, respectively.