Filling-Enforced Obstructed Atomic Insulators

Understand

Topological band theory has achieved great success in the high-throughput search for topological band structures both in paramagnetic and magnetic crystal materials.

• However, a significant proportion of materials are topologically trivial insulators at the Fermi level.
• In this paper, we show that, remarkably, for a subset of the topologically trivial insulators, knowing only their electron number and the Wyckoff positions of the atoms we can separate them into two groups: the obstructed atomic insulator (OAI) and the atomic insulator (AI).
• The interesting group, the OAI, have a center of charge not localized on the atoms.