Terahertz probing of temperature-driven topological phase transition in HgCdTe bulk crystal and HgTe Quantum Well

Bulk films and heterostructures based on HgCdTe compounds can be engineered to fabricate “gapped-at-will” structures. Therefore, 1D, 2D and even 3D massless particles can be observed in topological phase transitions driven by intrinsic (quantum well thickness, Cd content) and external (magnetic field, temperature, strain or hydrostatic pressure) physical parameters. In this work, we report on our experimental results, obtained by temperature-dependent Terahertz and Mid-Infrared magneto-spectroscopy, of topological phase transitions in HgCdTe-based Quantum Wells and bulk films. These transitions are accompanied with the appearance of 2D and 3D massless particles called Dirac and Kane fermions, respectively.