Abstract
Using a recently developed first-principles approach, we show that the variation in the superconducting behavior of group IVb and Vb transition metal carbides is associated with a significant nesting of the Fermi surfaces in group Vb compounds, while their phonon anomalies and density of states at the Fermi level play a minor role. The superconducting pairing arises from the coupling of metal states to acoustic phonons, and is therefore at variance with the interaction leading to the exceptional mechanical hardness where carbon states play a substantial role. We provide insight into how to optimize the transition temperature by varying the Fermi surface properties through substitutional doping.
- Received 8 April 2008
DOI:https://doi.org/10.1103/PhysRevB.77.180507
©2008 American Physical Society