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Sc substitution for Mg in MgB2: effects on Tc and Kohn anomaly

S. Agrestini·C. Metallo·M. Filippi·L. Simonelli·G. Campi·C. Sanipoli·E. Liarokapis·S. De Negri·M. Giovannini·A. Saccone·A. Latini·A. Bianconi
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Abstract

Here we report synthesis and characterization of Mg_{1-x}Sc_{x}B_{2} (0.12 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}.

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S. Agrestini, C. Metallo, M. Filippi, L. Simonelli, G. Campi, C. Sanipoli, E. Liarokapis, S. De Negri, M. Giovannini, A. Saccone, A. Latini, A. Bianconi. 2004-08-04. Sc substitution for Mg in MgB2: effects on Tc and Kohn anomaly. https://doi.org/10.1103/physrevb.70.134514

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