Pressure-induced high temperature superconductivity in H3X (X=As, Se, Br, Sb, Te and I).

The discovery of high critical temperature Tc 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 Im-3m structure for H3X (X=As, Se, Br, Sb, Te and I), We then applied the multiple scattering-based theory of Gaspari and Gyorffy to obtain the Hopfield parameters and the McMillan-Allen-Dynes theory to estimate lambda and Tc. Based on our analysis, all materials considered show an increase of the Hopfield parameters with increasing pressure for both the H and X-element components, which is a key ingredient for the strong electron-phonon coupling and the high Tc. Our calculations for H3Se, in agreement with other studies, find a Tc~110K. For the other materials in our study we obtain Tc well below 100 K. However, according to both of our rigid band model and virtual crystal analysis, we predict a Tc~180 K for H3Br with a small amount of additional of hydrogen.