Oscillating behavior of high-pressure stability observed in the immiscible Co-Cu system by first-principles calculation

Abstract

Based on the density functional perturbation theory, the phonon spectra of the immiscible Co-Cu compound under different pressures are calculated. It is found that the Co Cu3 compound can be stabilized under certain high pressure, further confirming the recently proposed concept of high-pressure alloying between immiscible elements [Dubrovinskaia, Phys. Rev. Lett. 95, 245502 (2005)]. Interestingly, alternately appearing imaginary phonons are observed under different pressures, suggesting that there exists an oscillation behavior of the stability of the Co Cu3 compound under high pressure, which deepens the understanding of the concept of high-pressure alloying between immiscible elements. © 2007 American Institute of Physics.