High pressure study of low-Z superconductor Be22Re

Lim, J., A. C. Hire, Y. Quan, J. Kim, L. Fanfarillo, S. R. Xie, R. S. Kumar, C. Park, R. J. Hemley, Y. K. Vohra, R. G. Hennig, P. J. Hirschfeld, G. R. Stewart, and J. J. Hamlin, High pressure study of low-Z superconductor Be22Re, arXiv:2104.01094.

With Tc∼9.6 K, Be₂₂Re exhibits one of the highest critical temperatures among Be-rich compounds. We have carried out a series of high-pressure electrical resistivity measurements on this compound to 30 GPa. The data show that the critical temperature T_c is suppressed gradually at a rate of dT_c/dP=−0.05 K/GPa. Using density functional theory (DFT) calculations of the electronic and phonon density of states (DOS) and the measured critical temperature, we estimate that the rapid increase in lattice stiffening in Be₂₂Re overwhelms a moderate increase in the electron-ion interaction with pressure, resulting in the decrease in T_c. High pressure x-ray diffraction measurements show that the ambient pressure crystal structure of Be₂₂Re persists to at least 154 GPa. We discuss the relationship between low-Z Be-rich superconductors and the high-T_c superhydrides.