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We present a complete theoretical treatment of Stark effects in doped silicon, whose predictions are supported by experimental measurements. A multi-valley effective mass theory, dealing non-perturbatively with valley-orbit interactions…

Regardless of various material design strategies, experimentally achieving substantial and controllable valley splitting in Si/SiGe quantum wells remains a central challenge for ensuring high gate uniformity. This difficulty arises from…

Mesoscale and Nanoscale Physics · Physics 2025-12-01 Yang Liu , Gang Wang , Shan Guan , Jun-Wei Luo , Shu-Shen Li

Exchange interactions among defects in semiconductors are commonly treated within effective-mass theory using a scaled hydrogenic wave-function. However such a wave-function is only applicable to shallow impurities; here we present a simple…

Materials Science · Physics 2009-11-13 W. Wu , A. J. Fisher

The ability to transport quantum information across some distance can facilitate the design and operation of a quantum processor. One-dimensional spin chains provide a compact platform to realize scalable spin transport for a solid-state…

Mesoscale and Nanoscale Physics · Physics 2016-08-17 Fahd A. Mohiyaddin , Rachpon Kalra , Arne Laucht , Rajib Rahman , Gerhard Klimeck , Andrea Morello

We develop a multi-valley effective mass theory for substitutional donors in silicon in an inhomogeneous environment. Valley-orbit coupling is treated perturbatively. We apply the theory to the Stark effect in Si:P. The method becomes more…

Materials Science · Physics 2009-11-11 Mark Friesen

Solid state spin qubits are promising candidates for the realization of a quantum computer due to their long coherence times and easy electrical manipulation. However, spin-spin interactions, which are needed for entangling gates, have only…

Mesoscale and Nanoscale Physics · Physics 2021-01-27 Lucia Gonzalez Rosado , Fabian Hassler , Gianluigi Catelani

We investigate the electrical control of the exchange coupling (J) between donor bound electrons in silicon with a detuning gate bias, crucial for the implementation of the two-qubit gate in a silicon quantum computer. We find the…

Mesoscale and Nanoscale Physics · Physics 2016-07-01 Yu E. Wang , Archana Tankasala , Lloyd C. L. Hollenberg , Gerhard Klimeck , Michelle Y. Simmons , Rajib Rahman

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…

Mesoscale and Nanoscale Physics · Physics 2015-04-07 M. Fernando Gonzalez-Zalba , André Saraiva , Dominik Heiss , Maria J. Calderón , Belita Koiller , Andrew J. Ferguson

Dielectric constant and absorption measurements on boron doped silicon samples show that transitions between the acceptor energy levels can be induced by an applied resonant ac electric field and the Stark tuning of level spacing with an…

Quantum Physics · Physics 2015-05-20 Y. P. Song , B. Golding

Research on Si quantum dot spin qubits is motivated by the long spin coherence times measured in Si, yet the orbital spectrum of Si dots is increased as a result of the valley degree of freedom. The valley degeneracy may be lifted by the…

Mesoscale and Nanoscale Physics · Physics 2015-05-18 Dimitrie Culcer , Lukasz Cywinski , Qiuzi Li , Xuedong Hu , S. Das Sarma

Donor spin in silicon have achieved record values of coherence times and single-qubit gate fidelities. The next stage of development involves demonstrating high-fidelity two-qubit logic gates, where the most natural coupling is the exchange…

Mesoscale and Nanoscale Physics · Physics 2021-08-11 Benjamin Joecker , Andrew D. Baczewski , John K. Gamble , Jarryd J. Pla , André Saraiva , Andrea Morello

The conduction band degeneracy in Si is detrimental to quantum computing based on spin qubits, for which a nondegenerate ground orbital state is desirable. This degeneracy is lifted at an interface with an insulator as the spatially abrupt…

Materials Science · Physics 2009-08-31 A. L. Saraiva , M. J. Calderón , Xuedong Hu , S. Das Sarma , Belita Koiller

Interface disorder and its effect on the valley degeneracy of the conduction band edge remains among the greatest theoretical challenges for understanding the operation of spin qubits in silicon. Here, we investigate a counterintuitive…

Mesoscale and Nanoscale Physics · Physics 2011-02-15 A. L. Saraiva , Belita Koiller , Mark Friesen

The nuclear spins of ionized donors in silicon have become an interesting quantum resource due to their very long coherence times. Their perfect isolation, however, comes at a price, since the absence of the donor electron makes the nuclear…

The performance and scalability of silicon spin qubits depend directly on the value of the conduction band valley splitting. In this work, we investigate the influence of electromagnetic fields and the interface width on the valley…

Mesoscale and Nanoscale Physics · Physics 2024-05-07 Jonas R. F. Lima , Guido Burkard

Quantum dots in SiGe/Si/SiGe heterostructures host coherent electron spin qubits, which are promising for future quantum computers. The silicon quantum well hosts near-degenerate electron valley states, creating a low-lying excited state…

SiGe heterostructures integrated with Si via virtual substrate (VS) growth are promising hosts for spin qubits. While VS growth targets plastic relaxation, residual cross-hatch strain inhomogeneity propagates into heterostructure…

Electronic spins in Silicon (Si) are rising contenders for qubits -- the logical unit of quantum computation-- owing to its outstanding spin coherence properties and compatibility to standard electronics. A remarkable limitation for spin…

Mesoscale and Nanoscale Physics · Physics 2015-06-15 Lijun Zhang , Jun-Wei Luo , A. L. Saraiva , Belita Koiller , Alex Zunger

We propose a quantum computer architecture involving substitutional donors in photonic-crystal silicon cavities and the optical initialization, manipulation, and detection processes already demonstrated in ion traps and other atomic…

Mesoscale and Nanoscale Physics · Physics 2008-11-25 M. Abanto , L. Davidovich , Belita Koiller , R. L. de Matos Filho

It has been over ten years since Kane's influential proposal for a silicon-based nuclear spin quantum computer using phosphorous donors. Since then, silicon-based architectures have been refined as the experimental challenges associated…

Quantum Physics · Physics 2009-05-26 John J. L. Morton