On the high pressure axial ratio anomaly in zinc and the roles of temperature and different electronic topological transitions

Abstract

We report electronic structure calculations on zinc at various compressions. Our calculations show that an electronic topological transition (ETT) associated with the anomaly in the axial ratio (c/a) at high pressures is sensitive to k sampling used in the calculations, exchange-correlation potential and temperature. We show that K-point ETT does not contribute to the anomaly, and thus disagree with the model of contributions from many ETTs. Hence only the L-point ETT is significant. We suggest that, even though temperature smearing of the Fermi function reduces the signatures of ETT, it does not wipe out the anomaly at room temperature.