First-principles calculations of electron-phonon coupling in NaSnSb: buckling and pressurization

In this paper, the electron-phonon coupling (EPC) properties of topological material NaSnSb has been explored, whose low phonon branch dominates the EPC constant lambda. NaSnSb can remain the strength of its EPC with a slight compression of the distance of the Na and Sb atoms along the z-axis (z (Na-Sb)), while further compression or stretching would destroy the strength of its EPC. By pressing, in the pressure range of 2 GPa, the superconducting transition temperature (T (c)) of NaSnSb behaves similar to that of FeSe in the same pressure range, with a local minimum at 1 GPa and a maximum at 1.5 GPa. Both compressing z (Na-Sb) and pressure lead to phonon softening of NaSnSb. The phonon softening induced by compressing z (Na-Sb) is three-dimensional, whereas the phonon softening induced by compression is two-dimensional.

Automated summary

In this paper, the electron-phonon coupling properties of NaSnSb topological material were investigated, with a predominant role of the low phonon branch in the EPC constant lambda. NaSnSb can maintain its EPC strength with a slight compression of the Na-Sb atomic distance along the z-axis, while further compression or stretching would weaken its EPC strength. Under pressure in the range of 2 GPa, the superconducting transition temperature of NaSnSb behaves similarly to FeSe, with a local minimum at 1 GPa and a maximum at 1.5 GPa. Both compression of z(Na-Sb) and pressure induce phonon softening in NaSnSb, with the former being three-dimensional and the latter being two-dimensional.