Novel electronic and phonon-related properties of the newly discovered silicide superconductor Li₂IrSi₃

¹ School of Physics and Electronic Information, Huaibei Normal University - Huaibei 235000, China
² College of Physics and Electronic Engineering, Zhengzhou University of Light Industry Zhengzhou 450002, China
³ Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences Hefei 230031, China
⁴ National Laboratory of Solid State Microstructures, Nanjing University - Nanjing 210093, China

^(a) luhongyan2006@sohu.com

Received: 27 March 2015
Accepted: 30 March 2015

Abstract

By means of first-principles calculations, we investigate the electronic structure, lattice dynamics, and electron-phonon coupling of the newly discovered silicide superconductor Li₂IrSi₃. The band structure shows obvious three-dimensional character, and the number of hole pockets around the center of the Brillouin zone depends on whether spin-orbit coupling is taken into consideration. For the phonon-related properties, a phononic-crystal–like behavior with a frequency gap in the range is discovered, which makes Li₂IrSi₃ a good candidate for controlling the propagation of phonons. The electron-phonon coupling constant λ equals 0.52, and the estimated superconducting transition temperature is close to its experimental value, suggesting that Li₂IrSi₃ is a weak-coupling phonon-mediated superconductor.