High Pressure study of (Axionic charge-density wave in the Weyl semimetal (TaSe4)2 and (NbSe4)2

An axion insulator is a correlated topological phase predicted to emerge from a charge-density wave (CDW) in a Weyl semimetal, where electrons behave as massless chiral fermions. The sliding phason mode of the CDW can act as an axion field and is expected to give rise to anomalous magnetoelectric responses. While theory provides a strong foundation, experimental confirmation of axionic CDWs has remained elusive.
We propose to answer several open questions:
How does pressure modify the microscopic mechanism underlying axionic transport?
Does the suppression or reinforcement of CDW order directly control the strength of the axion-like response?
Is there a critical regime under pressure where topology, correlations, and lattice dynamics conspire to create new emergent phases?