# Anomalous magnetic transport and extra quantum oscillation in semi-metallic photon-like fermion gas

## TL;DR

This paper explores the unique magnetic transport properties and quantum oscillations of a semi-metallic photon-like fermion gas, revealing novel gapless modes and their potential realization in materials.

## Contribution

It introduces the concept of gapless feroton modes in a semi-metallic photon-like fermion gas and demonstrates their impact on magnetic transport and quantum oscillations.

## Key findings

- Discovery of extra quantum oscillation behavior.
- Identification of gapless feroton modes with opposite chirality.
- Potential realization of feroton gas in real materials.

## Abstract

In the absence of Lorentz symmetry, the pseudospin-1 counterpart of Weyl fermion (feroton) with linear dispersions and an exact flat band can emerge in condensed matter systems. The flat band branch of feroton is equivalent to the longitudinal photon in Maxwell theory, which is a redundant degree of freedom due to the emergent (fermionic) gauge symmetry. Upon coupling to an external magnetic field, the fermionic guage symmetry is broken and the flat band ferotons become gapless excitations characterized by Landau level indices ($n>1$). In the long wave length limit, these gapless modes are of the opposite chirality to the chiral anomaly related zero Landau level, which leads to much more plentiful magnetic transport properties. To further explore the novel properties of these gapless modes, we investigate the quantum oscillation through a generalized Lieb lattice model. We find an extra oscillating behavior which indicates the existence of these exotic gapless modes. We collect known {\it ab initio} calculation data from literature and discuss the possibility of realizing the semi-metallic feroton gas in real materials.