ic9b02746_si_001.pdf (435.64 kB)
Pressure-Induced Structural Phase Transition and Superconductivity in NaSn5
journal contribution
posted on 2019-12-12, 18:34 authored by Chun-Mei Hao, Yunguo Li, Hong-Mei Huang, Yinwei Li, Yan-Ling LiThe structural and electronic properties of the tin-rich
compound NaSn5 were investigated under pressures of up
to 10 GPa on the basis of the evolutionary algorithm (EA) technique
coupled with first-principles total energy calculations. Upon compression,
the known metallic tetragonal P4̅21m phase transforms into a metallic hexagonal P6/mmm phase at 1.85 GPa accompanied by
an unusual change in the existing form of Sn atoms. The P6/mmm phase can be interpreted as a quasi-layered
sandwich structure with two Sn layers and one sodium layer. The presence
of softening phonon modes and the existence of Fermi pockets together
with the obvious Fermi surface nesting indicate a strong electron–phonon
coupling (EPC) and thus potential superconductivity in the P6/mmm phase. The strong EPC in the P6/mmm phase is mainly attributed to the
phonons from Sn1 atoms together with electrons from the Sn1 py and Sn1 pz states.
The calculated superconducting critical temperature Tc of the P6/mmm phase
is 5.91 K at 1.85 GPa. This study provides a new clue for designing
intercalated compounds with superconductivity.