Investigation of superconductivity in compressed vanadium hydrides

Abstract

Aiming at finding new superconducting materials, we performed systematical simulations on phase diagrams, crystal structures, and electronic properties of vanadium hydrides under high pressures. The VH, VH₂, VH₃, and VH₅ species were found to be stable under high pressures; among these, VH₂ had previously been investigated. Moreover, all three novel stoichiometries showed a strong ionic character as a result of the charge transfer from V to H. The electron–phonon coupling calculations revealed the potentially superconductive nature of these vanadium hydrides, with estimated superconducting critical temperature (T_c) values of 6.5–10.7 K for Rm (VH), 8.0–1.6 K for Fmm (VH₃), and 30.6–22.2 K for P6/mmm (VH₅) within the pressure range from 150 GPa to 250 GPa.