Band structure of new superconducting AlB_2-like ternary silicides M(Al_{0.5}Si_{0.5})_2 and M(Ga_{0.5}Si_{0.5})_2 (M= Ca, Sr and Ba)

TL;DR

This paper investigates the electronic band structures of new superconducting ternary silicides with AlB2-type structure, revealing that their transition temperatures are likely influenced by phonon-mode frequencies rather than density of states at the Fermi level.

Contribution

It provides detailed band structure calculations for M(Al_{0.5}Si_{0.5})_2 and M(Ga_{0.5}Si_{0.5})_2 superconductors, highlighting factors affecting their transition temperatures.

Findings

Transition temperatures do not correlate directly with d-states density at the Fermi level.

Phonon-mode frequencies are likely key to understanding superconducting transition temperatures.

The studied silicides exhibit superconductivity with T_c up to 7.7K.

Abstract

The electronic band structures of the new superconducting (with T_c up to 7.7K) ternary silicides M(A_{0.5}Si_{0.5})_2 (M= Ca, Sr, Ba; A= Al, Ga) in the AlB_2-type structure have been investigated using the full-potential LMTO method. The calculations showed that the trend in transition temperatures doesn't follow the changes in the density d-states at the Fermi level and probably is associated with phonon-mode frequencies.