We present a joint experimental and theoretical study of the superconducting phase of the layered binary silicide BaSi2. Compared with the layered AlB2 structure of graphite or diboride-like superconductors, in the hexagonal structure of binary silicides the sp3 arrangement of silicon atoms leads to corrugated sheets. Through a high-pressure synthesis procedure we are able to modify the buckling of these sheets, obtaining the enhancement of the superconducting transition temperature from 4 K to 8.7 K when the silicon planes flatten out. By performing ab-initio calculations based on density functional theory we explain how the electronic and phononic properties of the system are strongly affected by changes in the buckling. This mechanism is likely present in other intercalated layered superconductors, opening the way to the tuning of superconductivity through the control of internal structural parameters.
@article{arxiv.1011.1351,
title = {Enhancing the superconducting transition temperature of BaSi2 by structural tuning},
author = {José A. Flores-Livas and Régis Debord and Silvana Botti and Alfonso San Miguel and Miguel A. L. Marques and Stéphane Pailhès},
journal= {arXiv preprint arXiv:1011.1351},
year = {2015}
}