Superconductivity in Li-intercalated bilayer arsenene and hole-doped monolayer arsenene: a first-principles prediction

Abstract

Using first-principles calculations, we find Li-intercalated bilayer arsenene with AB stacking is dynamically stable, which is different from pristine bilayer with AA stacking. Electron–phonon coupling of the stable Li-intercalated bilayer arsenene are dominated by the low frequency vibrational modes (E″(1), (1), E′(1) and acoustic modes) and lead to an superconductivity with Tc = 8.68 K with isotropical Eliashberg function. Small biaxial tensile strain (2%) can improve Tc to 11.22 K due to the increase of DOS and phonon softening. By considering the fully anisotropic Migdal–Eliashberg theory, Tc are found to be enhanced by 50% and exhibits a single anisotropic gap nature. In addition, considering its nearly flat top valence band which is favorable for high temperature superconductivity, we also explore the superconducting properties of hole-doped monolayer arsenene under different strains. the unstrained monolayer arsenene superconducts at Tc = 0.22 K with 0.1 hole/cell doping. By applying 3% biaxial strain, Tc can be lifted up strikingly to 6.69 K due to a strong Fermi nesting of the nearly flat band. Then Tc decreases slowly with strain. Our findings provide another insight to realize 2D superconductivity and suggest that the strain is crucial to further enhance the transition temperature.