Making Massless Dirac Fermions from Patterned Two-Dimensional Electron Gases

TL;DR

This paper demonstrates that applying a specific hexagonal periodic potential to a two-dimensional electron gas can produce massless Dirac fermions, offering a new platform beyond graphene for studying these particles.

Contribution

The study shows how to generate and tune massless Dirac fermions in 2DEGs using experimentally feasible external potentials, expanding possibilities for semiconductor-based Dirac physics.

Findings

Massless Dirac fermions appear near supercell Brillouin zone corners.

Group velocity is tunable via effective mass and lattice parameter.

Potential amplitude has negligible effect on Dirac fermion properties.

Abstract

Analysis of the electronic structure of an ordinary two-dimensional electron gas (2DEG) under an appropriate external periodic potential of hexagonal symmetry reveals that massless Dirac fermions are generated near the corners of the supercell Brillouin zone. The required potential parameters are found to be achievable under or close to laboratory conditions. Moreover, the group velocity is tunable by changing either the effective mass of the 2DEG or the lattice parameter of the external potential, and it is insensitive to the potential amplitude. The finding should provide a new class of systems other than graphene for investigating and exploiting massless Dirac fermions using 2DEGs in semiconductors.