Compressed Crystalline Bismuth and Superconductivity-An ab initio computational Simulation

TL;DR

This study uses ab initio simulations to investigate how pressure affects crystalline bismuth's electronic and vibrational properties, concluding that mere compression without structural change does not induce superconductivity.

Contribution

It provides new insights into the electronic and vibrational changes in bismuth under pressure, emphasizing the importance of structural transformations for superconductivity.

Findings

Pure compression of crystalline bismuth does not induce superconductivity.

Structural changes are likely necessary for superconductivity in bismuth.

Electronic and vibrational state densities are key factors in superconductivity behavior.

Abstract

Bismuth displays puzzling superconducting properties. In its crystalline equilibrium phase, it does not seem to superconduct at accessible low temperatures. However, in the amorphous phase it displays superconductivity at ~ 6 K. Under pressure bismuth has been found to superconduct at Tcs that go from 3.9 K to 8.5 K depending on the phase obtained. So the question is: what electronic or vibrational changes occur that explains this radical transformation in the conducting behavior of this material? In a recent publication we argue that changes in the density of electronic and vibrational states may account for the behavior observed in the amorphous phase with respect to the crystal. We have now undertaken an ab initio computational study of the effects of pressure alone maintaining the original crystalline structure and compressing our supercell computationally. From the results obtained we infer that if the crystal structure remains the same (except for the contraction), no superconductivity will appear.