Revealing temperature evolution of the Dirac band in ZrTe5 via magnetoinfrared spectroscopy

The topological phases and their dependence on the lattice constant in zirconium pentatelluride ZrTe${}_{5}$ have been under heated debate. Here, the authors study the temperature evolution of the Dirac band in ZrTe${}_{5}$ and find no indication of band-gap closure as temperature changes. They show that a weak topological insulator phase across the temperature range may not be the only explanation. A topological phase transition is still possible if the band mixing and inversion are considered.