# Massless Dirac fermions in III-V semiconductor quantum wells

## TL;DR

This paper provides experimental evidence of massless Dirac fermions in III-V semiconductor quantum wells, demonstrating a gapless state and linear band crossing, with detailed analysis of their velocity and dispersion characteristics.

## Contribution

It is the first to experimentally confirm massless Dirac fermions in III-V semiconductors using magnetotransport and cyclotron resonance measurements.

## Key findings

- Identification of a gapless state in InAs/GaSb/InAs quantum wells.
- Direct measurement of linear band crossing at the Γ point.
- Determination of Dirac fermion velocity and non-linear dispersion at high energies.

## Abstract

We report on the clear evidence of massless Dirac fermions in two-dimensional system based on III-V semiconductors. Using a gated Hall bar made on a three-layer InAs/GaSb/InAs quantum well, we restore the Landau levels fan chart by magnetotransport and unequivocally demonstrate a gapless state in our sample. Measurements of cyclotron resonance at different electron concentrations directly indicate a linear band crossing at the $\Gamma$ point of Brillouin zone. Analysis of experimental data within analytical Dirac-like Hamiltonian allows us not only determing velocity $v_F=1.8\cdot10^5$ m/s of massless Dirac fermions but also demonstrating significant non-linear dispersion at high energies.