Giant Hall effect in two-dimensional CoSi2 granular arrays

Granular metals offer tailorable electronic properties and play crucial roles in device and sensor applications. We have fabricated a series of nonmagnetic granular ${\mathrm{CoSi}}_2$ thin films and studied the Hall effect and transport properties. We observed a two-order magnitude enhancement in the Hall coefficient in films that fall slightly above the metal-insulator transition. This giant Hall effect (GHE) is ascribed to the local quantum-interference effect-induced reduction of the charge carriers. Transmission electron microscopy images and transport properties indicate that our films form quasi-two-dimensional granular arrays. The GHE may provide useful and sensitive applications.