Ab initio Modeling of Superconducting Materials by Exploring Excited Electronic Configurations*

High pressure hydrogen sulfide is a great candidate for industrial applications as a high temperature superconductor such as being used for frictionless railway systems and zero-resistance circuits at power plants as a way to efficiently transfer current. Hydrogen sulfide keeps its superconducting properties up to 200K when at extreme pressure. We mimic the electronic configuration features of this material relevant to superconductivity which includes constraints to spin projection, momentum by using spin polarized calculations and including momentum dispersion via k-points. K-points are included such that we can mimic a large segment of a material while explicitly simulating just a single unit cell.

This research shows that Cooper pairs are available to form in the sulfur trihydride material and can serve as the reason for superconductivity. Cooper pairs are formed when two electrons have opposite values of spin and momentum interacting via the distortion of the lattice. We computed the total energy for a range of relevant multi electronic configurations and compared it to the total energy of the reference neutral singlet configuration. We then introduce nuclear reorganization as part of our calculations.

We find that the energy of the certain excited states are more energetically favorable than the energy of the ground state. These more energetically favorable states are the states where Cooper pairs can form which is the primary reason for superconductivity.