A first-principles investigation of the origin of superconductivity in TlBi${}_2$

Abstract

The intermetallic compound TlBi${}_2$ crystallizes in the MgB${}_2$ structure and becomes superconducting below 6.2 K. Considering that both Tl and Bi have heavy atomic masses, it is puzzling why TlBi${}_2$ is a conventional phonon-mediated superconductor. We have performed comprehensive first-principles calculations of the electronic structures, the phonon dispersions and the electron-phonon couplings for TlBi${}_2$. The $6p$ orbitals of bismuth dominate over the states near the Fermi level, forming strong intra-layer $p_{x/y}$ and inter-layer $p_z$ $\sigma$ bonds which is known to have strong electron-phonon coupling. In addition, the large spin-orbit coupling interaction in TlBi${}_2$ increases its electron-phonon coupling constant significantly. As a result, TlBi${}_2$, with a logarithmic phonon frequency average one tenth that of MgB${}_2$, is a phonon-mediated superconductor.

References in corpus (11)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Advanced capabilities for materials modelling with Quantum ESPRESSO
• Topological Insulators with Inversion Symmetry
• Superconductivity near 80 Kelvin in single crystals of La3Ni2O7 under pressure
• Fermi surface nesting and the origin of Charge Density Waves in metals
• Three-dimensional MgB${}_2$-type superconductivity in hole-doped diamond
• Origin of Superconductivity in Boron-doped Diamond
• Superconductive materials with MgB2-like structures from data-driven screening
• Doping-induced superconductivity of ZrB${}_2$ and HfB${}_2$
• Experimental evidence of monolayer AlB${}_2$ with symmetry-protected Dirac cones
• Superconductivity in TlBi${}_2$ with a large Kadowaki-Woods ratio

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• Electron correlations and superconductivity in La${}_3$Ni${}_2$O${}_7$ under pressure tuning
• Discovery of superconductivity in technetium-borides at moderate pressures
• Phonon-mediated superconductivity in transition-metal trioxides XO3 (X = Ru, Re, Os, Ir, Pt) under pressure