An Exchange-Coupled Donor Molecule in Silicon

Abstract

Donors in silicon, conceptually described as hydrogen atom analogues in a semiconductor environment, have become a key ingredient of many "More-than-Moore" proposals such as quantum information processing [1-5] and single-dopant electronics [6, 7]. The level of maturity this field has reached has enabled the fabrication and demonstration of transistors that base their functionality on a single impurity atom [8, 9] allowing the predicted single-donor energy spectrum to be checked by an electrical transport measurement. Generalizing the concept, a donor pair may behave as a hydrogen molecule analogue. However, the molecular quantum mechanical solution only takes us so far and a detailed understanding of the electronic structure of these molecular systems is a challenge to be overcome. Here we present a combined experimental-theoretical demonstration of the energy spectrum of a strongly interacting donor pair in the channel of a silicon nanotransistor and show the first observation of measurable two-donor exchange coupling. Moreover, the analysis of the three charge states of the pair shows evidence of a simultaneous enhancement of the binding and charging energies with respect to the single donor spectrum. The measured data are accurately matched by results obtained in an effective mass theory incorporating the Bloch states multiplicity in Si, a central cell corrected donor potential and a full configuration interaction treatment of the 2-electron spectrum. Our data describe the basic 2-qubit entanglement element in Kane's quantum processing scheme [1], namely exchange coupling, implemented here in the range of molecular hybridization.

9 pages, 5 figures

References in corpus (4)

• Transport spectroscopy of a single dopant in a gated silicon nanowire
• Single-shot readout and relaxation of singlet/triplet states in exchange-coupled ${}^{31}$P electron spins in silicon
• Detection of a large valley-orbit splitting in silicon with two-donor spectroscopy
• Heterointerface effects on the charging energy of shallow D- ground state in silicon: the role of dielectric mismatch

Cited by in corpus (28)

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• Quantum and Tunnelling Capacitance in Charge and Spin Qubits
• Adequacy of Si:P Chains as Fermi-Hubbard Simulators
• Multivalley effective mass theory simulation of donors in silicon
• Engineering inter-qubit exchange coupling between donor bound electrons in silicon
• Conditional quantum operation of two exchange-coupled single-donor spin qubits in a MOS-compatible silicon device
• Theory of one and two donors in Silicon
• Hole spin resonance and spin-orbit coupling in a silicon metal-oxide-semiconductor field-effect transistor
• Valley interference and spin exchange at the atomic scale in silicon
• Full configuration interaction simulations of exchange-coupled donors in silicon using multi-valley effective mass theory
• Transport of Spin Qubits with Donor Chains under Realistic Experimental Conditions
• Roadmap on Atomic-scale Semiconductor Devices
• Donor Wavefunctions in Si Gauged by STM Images
• Valley filtering and spatial maps of coupling between silicon donors and quantum dots
• Statistical exchange-coupling errors and the practicality of scalable silicon donor qubits
• Linear and planar molecules formed by coupled P donors in silicon
• Interface effects on acceptor qubits in silicon and germanium
• The impact of nuclear spin dynamics on electron transport through donors
• Application of single-electron effects to fingerprints of chips using image recognition algorithms
• Spin-orbit coupling induced two-electron relaxation in silicon donor pairs
• 2-dimensional semiconductors pave the way towards dopant based quantum computing
• Bardeen's tunneling theory applied to intraorbital and interorbital hopping integrals between dopants in silicon
• Donors in Ge as Qubits: Establishing Physical Attributes
• Disordered Si:P nanostructures as switches and wires for nanodevices