# Suppressed Auger scattering and tunable light emission of Landau-quantized massless Kane electrons

## TL;DR

This study demonstrates that massless Kane electrons in gapless HgCdTe exhibit suppressed Auger scattering, enabling tunable Landau level laser emission in the THz and infrared ranges, overcoming previous material limitations.

## Contribution

It reveals that gapless HgCdTe suppresses Auger scattering in massless Kane electrons, allowing for reliable Landau level laser operation with tunable emission.

## Key findings

- Suppressed Auger scattering in gapless HgCdTe with Kane electrons.
- Observation of sizeable cyclotron emission in this material.
- Potential of HgCdTe for future Landau level laser technology.

## Abstract

The Landau level laser has been proposed a long time ago as a unique source of monochromatic radiation, widely tunable in the THz and infrared spectral ranges using an externally applied magnetic field. In spite of decades of efforts, this appealing concept never resulted in the design of a reliable device. This is due to efficient Auger scattering of Landau-quantized electrons, which is an intrinsic non-radiative recombination channel that eventually gains over cyclotron emission in all materials studied so far: in conventional semiconductors with parabolic bands, but also in graphene with massless electrons. The Auger processes are favored in these systems by Landau levels (or their subsets) equally spaced in energy. Here we show that this scheme does not apply to massless Kane electrons in gapless HgCdTe alloy, in which undesirable Auger scattering is strongly suppressed and the sizeable cyclotron emission observed, for the first time in the case of massless particles. The gapless HgCdTe thus appears as a material of choice for future technology of Landau level lasers.