Nb₃I₈ (Niobium Triiodide Cluster Compound)

Nb₃I₈ (Niobium Triiodide Cluster Compound) — Introduction

Nb₃I₈ is a cluster-based niobium iodide with a low-dimensional layered structure. It has attracted attention due to its Mott-insulating behavior and potential as a correlated electron system.

Physical Properties

Appearance: Dark-red to black crystalline solid.

Crystal Structure: Built from triangular Nb₃ clusters, coordinated by iodine atoms. The layered packing allows for quasi-2D physics.

Electronic Properties: Exhibits a narrow band gap (~0.4–0.6 eV), making it a small-gap semiconductor or Mott insulator.

Exfoliation: The layered nature allows for exfoliation, though the stronger cluster–cluster interactions make it more difficult to isolate monolayers compared to typical van der Waals materials.

Applications

Quantum Materials: A platform for studying correlated states, including Mott insulating phases and possible quantum spin liquid behavior.

Infrared Optoelectronics: Narrow band gap makes it suitable for near-infrared photodetectors.

Spintronics: Correlated magnetism from Nb–Nb cluster interactions may be harnessed in spintronic devices.