Chemical control of electronic structure and superconductivity in layered borides and borocarbides: understanding the absence of superconductivity in LixBC.
The synthetic search for materials related to the 39 K superconductor MgB2 has been difficult. The most promising theoretical suggestion, hole doping of LiBC, does not lead to a new superconductor. We show here that a combination of density functional theory (DFT) calculations, materials synthesis, and structural characterization reveals the origin of the puzzling absence of superconductivity in Li1/2BC as a subtle change in the electronic structure driven by structural response to the introduction of holes. This indicates that the unique aspects of the electronic structure of MgB2 will be demanding to replicate in other systems.
Fogg
Andrew M
AM
Department of Chemistry, The University of Liverpool, Liverpool, L69 7ZD United Kingdom.
Meldrum
James
J
Darling
George R
GR
Claridge
John B
JB
Rosseinsky
Matthew J
MJ