Coherent Emission in the Vicinity of 10 THz due to Auger-Suppressed Recombination of Dirac Fermions in HgCdTe Quantum Wells

The discovery of Dirac fermions in a number 2D and 3D materials boosted the solid-state research an unprecedented way. Among many hopes using their exceptional physical properties, it has been argued that reduced nonradiative losses would allow graphene to compete with quantum cascade lasers (QCLs) race for terahertz (THz) emitters. Unfortunately, Auger recombination (AR) process is still active massless gapless graphene. However, massive fermions, AR can be entirely suppressed below certain threshold carrier’s kinetic energy depends on nonparabolicity symmetry electron hole dispersions. In this work, by finely tuning band structure HgCdTe wells hosting we set electronic system demonstrate carrier purely radiative. A coherent interband emission reaching 9.6 THz, say outside spectral range current QCLs, measured under these conditions, opening way lossless THz