Axial Higgs Mode Detected by Raman Scattering in RTe3

The observation of the Higgs boson solidified the standard model of particle physics. However, explanations of anomalies (e.g. dark matter) rely on further symmetry breaking calling for a yet-to-be-discovered axial Higgs mode. In condensed matter, the Higgs mode has been observed in magnetic, superconducting, and charge density wave systems (CDW), and is typically assumed to have a scalar representation. Uncovering the vector properties of a low energy mode is extremely challenging, requiring going beyond typical spectroscopic or scattering techniques to reveal the hidden aspects of their wavefunctions. Here we set up a simple optical scheme and discover an unconventional axial Higgs mode in the 2D material GdTe3, which also has high mobility and antiferromagnetic order. The Axial Higgs mode is revealed using the interference of excitation quantum pathways in Raman scattering. I will discuss how the Axial Higgs mode emerges from the combination of the quantum geometry of the Fermi surface and the charge density wave, opening opportunities for new topological correlated states in 2D systems.