Electronic Structure of the Topological Insulator ZrTe₅ by First-Principles

The topological insulator (TI), ZrTe₅, has attracted significant attention as a candidate hosting a three-dimensional quantum Hall effect, an uncommon phenomenon in bulk materials. A metal-to-insulator transition in ZrTe₅ is readily induced when external perturbations are applied such as strain. This structural tunability provides a platform to study the controllable electronic structure in materials with a narrow bulk band gap, particularly the transition between strong and weak TI phases. In this study, we use first-principles calculations and spin angle-resolved photoemission spectroscopy to reveal a high degree of spin polarization in the surface states and demonstrate clear spin-momentum locking, confirming the topological nature of the system.