qeirreps: an open-source program for Quantum ESPRESSO to compute irreducible representations of Bloch wavefunctions

Understand

Bloch wavefunctions in solids form a representation of crystalline symmetries.

• Recent studies revealed that symmetry representations in band structure can be used to diagnose the topological properties of weakly interacting materials.
• In this work, we introduce an open-source program qeirreps that computes the representation characters in a band structure based on the output file of Quantum ESPRESSO.
• Our program also calculates the Z4 index, i.e., the sum of inversion parities at all time-reversal invariant momenta, for materials with inversion symmetry.