Here we report synthesis and characterization of Mg_{1-x}Sc_{x}B_{2} (0.12<x<0.27) system, with critical temperature in the range of 30>T_{c}>6 K. We find that the Sc doping moves the chemical potential through the 2D/3D electronic topological transition (ETT) in the sigma band where the ``shape resonance" of interband pairing occurs. In the 3D regime beyond the ETT we observe a hardening of the E_{2g} Raman mode with a significant line-width narrowing due to suppression of the Kohn anomaly over the range 0<q<2k_{F}.
@article{arxiv.cond-mat/0408095,
title = {Sc substitution for Mg in MgB2: effects on Tc and Kohn anomaly},
author = {S. Agrestini and C. Metallo and M. Filippi and L. Simonelli and G. Campi and C. Sanipoli and E. Liarokapis and S. De Negri and M. Giovannini and A. Saccone and A. Latini and A. Bianconi},
journal= {arXiv preprint arXiv:cond-mat/0408095},
year = {2008}
}
Comments
8 pages, 4 EPS figures, to be published in Phys. Rev. B