An exchange-coupled donor molecule in silicon.

Abstract

This study presents a combined experimental and theoretical analysis of the energy spectrum and exchange coupling of an isolated donor pair embedded in a silicon nanotransistor. Molecular hybridization of atomic orbitals was found to increase one- and two-electron binding energies as well as charging energy relative to the single-donor configuration, a property considered advantageous for quantum electronic device applications. A hydrogen molecule-like theoretical framework employing multivalley central-cell corrected effective mass theory with full configuration interaction treatment of the two-electron spectrum successfully reproduced measured data corresponding to an arsenic diatomic molecule at an interatomic separation of 2.3 ± 0.5 nm.