Pressure-enhanced high temperature superconductivity in XH3 (X=As, Se, Br, Sb, Te and I)

The discovery of high critical temperature T_c superconductivity in highly compressed H3S has
opened up the question of searching for strong electron-phonon coupling in the hydrides outside
the transition metal series. In this work, we performed linearized augmented plane wave (LAPW)
calculations for many different volumes in the Im3m structure for XH3 (X=As,Se,Br,Sb,Te and I),
We then applied the multiple scattering-based theory of Gaspari and Gyorffy to obtain the
Hopfiled parameters and the McMillan–Allen–Dynes theory to estimate λ and T_c. Based on
our analysis, all considered materials share similar trends of T_c enhancement under
increasing pressure. H3Se in particular, could potentially go to a T_c well over 200 K. Finally,
in addition to pressure enhanced electron-phonon coupling, by applying rigid band model we
predict that a small amount of alloying with a neighboring element could lead to even further
increase of T_c