  The microscopic properties of few interacting cold fermionic atoms confined
in a two-dimensional (2D) harmonic trap are studied by numerical
diagonalization. For repulsive interactions, a strong shell structure
dominates, with Hund's rule acting at its extreme for the mid-shell
configurations. In the attractive case, odd-even oscillations due to pairing
occur simultaneously with deformations in the internal structure of the ground
states, as seen from pair correlation functions.

Mesoscale and Nanoscale Physics;Other Condensed Matter