Strong particle-hole asymmetry in a 200 Kelvin superconductor

The superconducting state of metals have long provided a classic example of particle-hole symmetry at low energy. We present fermionic self-energy results based on first-principles theory for the electron-phonon coupling in H₃S which illustrates strong particle-hole asymmetry in the dynamics arising from the underlying sharp structure in the fermionic density of states. We evaluate the momentum-resolved and zone-averaged spectral densities and interacting thermal distribution function, all of which clearly illustrate strong particle-hole asymmetry. The results allow us to study the infrared conductivity and to note that the strength and position of extrema are affected by electron-phonon coupling.