Quantum wires and dots induced in a semiconductor by charged metallic filaments separated by an isolating barrier

A very thin positively charged metallic filament separated from a surface of a semiconductor (S) by a thin nontunneling potential barrier (B) induces a quantum wire (QWr) in the semiconductor at the B/S interface. Single-electron quantum states of this QWr are controlled by a potential (and a charge) of the metallic filament. Two close parallel metallic filaments placed over such a B/S interface form a double-quantum wire with the ground and the first excited electron states, which appear as a result of a symmetric-antisymmetric splitting of the ground electron state in the single QWr. Two crossed metallic filaments, which are parallel to the B/S interface, form a quantum dot with completely localized electron states under the crossing point of the metallic filaments. The analogous crossing of a metallic filament by a pair of close metallic filaments forms a double-quantum dot (DQD). The latter can serve as a two-level qubit cell. Such qubits can be controlled by potentials of three independent metallic filaments inducing the above-mentioned DQD. Besides this "outside" metallic wire control, the DQDs can be connected to each other across the "inside" quantum wires, which have formed these DQDs by crossing. (C) 2005 American Institute of Physics.