One-dimensional quantum-wire states probed by resonant electron tunneling

We have resolved the bound states of a one-dimensional quantum wire by resonant electron tunneling. The atomically precise quantum-confined structure was prepared by cleaved-edge overgrowth in GaAs/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As molecular-beam epitaxy. Tunneling proceeded, in a planar geometry, from the edge of a two-dimensional electron source through the bound states of the quantum wire into the edge of a two-dimensional electron drain. The experimental resonance positions, as well as their density dependences, are well reproduced by our self-consistent theoretical calculations.