CONFINEMENT OF ELECTRONS TO QUANTUM CORRALS ON A METAL-SURFACE

A method for confining electrons to artificial structures at the nanom eter lengthscale is presented. Surface state electrons on a copper(111 ) surface were confined to closed structures (corrals) defined by barr iers built from iron adatoms. The barriers were assembled by individua lly positioning iron adatoms with the tip of a 4-kelvin scanning tunne ling microscope (STM). A circular corral of radius 71.3 angstrom was c onstructed in this way out of 48 iron adatoms. Tunneling spectroscopy performed inside of the corral revealed a series of discrete resonance s, providing evidence for size quantization. STM images show that the corral's interior local density of states is dominated by the eigensta te density expected for an electron trapped in a round two-dimensional box.