title: An exchange-coupled donor molecule in silicon.
abstract: We present a combined experimental-theoretical demonstration of the energy spectrum and exchange coupling of an isolated donor pair in a silicon nanotransistor. The molecular hybridization of the atomic orbitals leads to an enhancement of the one- and two-electron binding energies and charging energy with respect to the single donor case, a desirable feature for quantum electronic devices. Our hydrogen molecule-like model based on a multivalley central-cell corrected effective mass theory incorporating a full configuration interaction treatment of the 2-electron spectrum matches the measured data for an arsenic diatomic molecule with interatomic distance R = 2.3 ± 0.5 nm.
authors.affiliation: Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge CB3 0HE, U.K.
authors.forename: M F
authors.initials: MF
authors.lastname: Gonzalez-Zalba
authors.forename: André
authors.initials: A
authors.lastname: Saraiva
authors.forename: María J
authors.initials: MJ
authors.lastname: Calderón
authors.forename: Dominik
authors.initials: D
authors.lastname: Heiss
authors.forename: Belita
authors.initials: B
authors.lastname: Koiller
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Ferguson
keywords: Quantum computing; dopants; exchange coupling; quantum chemistry; silicon; transistor