Electronic topological transition in zinc metal at high external pressure

Abstract

We report investigations of Zn metal under quasi-hydrostatic pressures up to 16 GPa by Mössbauer spectroscopy and scalar - relativistic linearized augmented plane wave (LAPW) calculations. Our studies show that at 4.2 K an electronic topological transition (ETT) occurs at about 6.6 GPa, corresponding to a volume change of . At the ETT conduction electron states in the third Brillouin zone at the symmetry point L (`butterflies') move below the Fermi surface and start being occupied. At the ETT the electric field gradient tensor and the s electron density at the nucleus remain virtually unchanged, but the lattice dynamics is drastically affected. The Lamb - Mössbauer factor (LMF) abruptly drops by a factor of two between 6.5 and 6.7 GPa and the curvature of the pressure dependence of the second-order Doppler shift changes markedly. The results on LMF and are described by a sudden destruction of a giant Kohn anomaly which accompanies the ETT.