Effects of the Spin-Orbit Coupling and the Superconductivity in simple-cubic alpha-Polonium

TL;DR

This study reveals how strong spin-orbit coupling stabilizes the simple-cubic structure of alpha-Polonium and predicts its potential superconductivity with a transition temperature around 4 K, highlighting the role of phonon modes.

Contribution

It demonstrates the stabilizing effect of spin-orbit coupling on alpha-Polonium's structure and predicts its superconducting properties based on phonon dispersion calculations.

Findings

Strong SOC suppresses Peierls instability in alpha-Po

Alpha-Po is predicted to be a superconductor with Tc ~ 4 K

Soft phonon modes influenced by SOC are key to stability and superconductivity

Abstract

We have investigated the mechanism of stabilizing the simple-cubic (SC) structure in polonium (alpha- Po), based on the phonon dispersion calculations using the first-principles all-electron band method. We have demonstrated that the stable SC structure results from the suppression of the Peierls instability due to the strong spin-orbit coupling (SOC) in alpha-Po. Further, we have explored the possible superconductivity in alpha-Po, and predicted that it becomes a superconductor with Tc ~ 4 K. The transverse soft phonon mode at q ~ 2/3 R, which is greatly influenced by the SOC, plays an important role both in the structural stability and the superconductivity in alpha-Po. We have discussed effects of the SOC and the volume variation on the phonon dispersions and superconducting properties of alpha-Po.