Mode coupling in liquid Zn. An ab-initio molecular dynamics study.

The static and dynamic properties of liquid Zn have been studied using an ab initio molecular dynamics method. Results are reported for the thermodynamic states at 723 K for which inelastic neutron scattering data are available [1]. The calculated static structure shows very good agreement with experimental measurements, including an asymmetric second peak. The dynamic structure reveals the existence of a second propagating mode in both the longitudinal and transverse current correlation functions. We explain this anomaly, previously observed in other liquid metals under high pressure [2], using Sjögren and Sjölander mode coupling theory (MCT) [3]. The MCT provides a satisfactory description of the results although, it lacks accuracy in some wavevector regions. Nevertheless, it provides a first step in the understanding of an interesting phenomenom that is starting to be observed in liquid metals and that, up to now, was thought to only appear at high pressures. [1] M. Zanatta et al, Phys. Rev. Lett. 114, 187801 (2015) [2] T. Bryk et al, J. Chem. Phys. 143, 104502 (2015); M. Marqués et al, J. Phys. Condens. Matter 28, 075101 (2016) [3] L. Sjögren, Phys. Rev. A 22, 2883 (1980)