Unveiling the Chiral States in Multi-Weyl Semimetals via Theoretical Investigation of Magneto-Optical Spectroscopy

The multiple zeroth Landau levels (LLs) in multi-Weyl semimetals (mWSMs), also called chiral states, are fundamental to their distinctive transport and optical properties. This study investigates the transport parameters of mWSMs, with a focus on their magneto-optical response and the critical influence of such multiple zeroth states. Our theoretical analysis highlights the tilting parameters as key determinants in higher-order Weyl nodes, significantly modulating the magneto-optical behavior. A generic LL expression for mWSMs is derived, offering a solid theoretical framework for understanding their quantum transport properties. Comprehensive expressions for the conductivity tensor components are presented, revealing distinctive low-frequency peaks originating from the optical transitions between chiral states as well as that between the bulk and the chiral states. These features are strongly influenced by the tilting parameters, which consequently dictate the low-frequency optical response. These features extend to the Faraday and Kerr rotation spectra, prominently signaling chiral states at frequencies near the tilted Dirac cone. These findings underscore the fundamental role of robust chiral states in the magneto-optical behavior of mWSMs, advancing our understanding of their topological phenomena.