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We perform an excited state spectroscopy analysis of a silicon corner dot in a nanowire field-effect transistor to assess the electric field tunability of the valley splitting. First, we demonstrate a back-gate-controlled transition between…

We investigate the effect of the valley degree of freedom on Pauli-spin blockade readout of spin qubits in silicon. The valley splitting energy sets the singlet-triplet splitting and thereby constrains the detuning range. The valley phase…

Mesoscale and Nanoscale Physics · Physics 2018-06-20 M. L. V. Tagliaferri , P. L. Bavdaz , W. Huang , A. S. Dzurak , D. Culcer , M. Veldhorst

Electron spins in silicon quantum dots are excellent qubits because they have long coherence times, high gate fidelities, and are compatible with advanced semiconductor manufacturing techniques. The valley degree of freedom, which results…

Mesoscale and Nanoscale Physics · Physics 2023-03-27 Xinxin Cai , Elliot J. Connors , John M. Nichol

We present the theory and measurement of valley splitting in a quantum point contact (QPC) in a modulation doped Si/SiGe heterostructure. Our measurements are performed on a submicron Schottky-gated device. An effective mass theory is…

Mesoscale and Nanoscale Physics · Physics 2010-03-30 L. M. McGuire , Mark Friesen , K. A. Slinker , S. N. Coppersmith , M. A. Eriksson

(001) Si spin qubits are being intensively studied because they have structures similar to that of CMOS devices currently being produced, and thus have the advantage of utilizing state-of-the-art miniaturization, integration, and…

Quantum Physics · Physics 2025-01-24 Takafumi Tokunaga , Hiromichi Nakazato

Although silicon is a promising material for quantum computation, the degeneracy of the conduction band minima (valleys) must be lifted with a splitting sufficient to ensure formation of well-defined and long-lived spin qubits. Here we…

Mesoscale and Nanoscale Physics · Physics 2013-07-01 C. H. Yang , A. Rossi , R. Ruskov , N. S. Lai , F. A. Mohiyaddin , S. Lee , C. Tahan , G. Klimeck , A. Morello , A. S. Dzurak

Valleytronics, as an alternative to traditional electronics or spintronics, is based on the encoding of quantum information in pseudospin valley quantum numbers, rather than in charge or spin states. A key ingredient is the (optical)…

Understanding crystal characteristics down to the atomistic level increasingly emerges as a crucial insight for creating solid state platforms for qubits with reproducible and homogeneous properties. Here, isotope composition depth profiles…

Spin shuttling has crystalized as a powerful and promising tool for establishing intermediate-range connectivity in semiconductor spin-qubit devices. Although experimental demonstrations have performed exceptionally well on different…

Mesoscale and Nanoscale Physics · Physics 2026-04-16 Nicklas Meineke , Guido Burkard

Large-scale arrays of quantum-dot spin qubits in Si/SiGe quantum wells require large or tunable energy splittings of the valley states associated with degenerate conduction band minima. Existing proposals to deterministically enhance the…

Coherent manipulation of binary degrees of freedom is at the heart of modern quantum technologies. Graphene offers two binary degrees: the electron spin and the valley. Efficient spin control has been demonstrated in many solid state…

Electrical transport in double quantum dots (DQDs) illuminates many interesting features of the dots' carrier states. Recent advances in silicon quantum information technologies have renewed interest in the valley states of electrons…

Mesoscale and Nanoscale Physics · Physics 2017-11-15 Justin K. Perron , Michael J. Gullans , Jacob M. Taylor , M. D. Stewart, , Neil M. Zimmerman

The electrical control of single spin qubits based on semiconductor quantum dots is of great interest for scalable quantum computing since electric fields provide an alternative mechanism for qubit control compared with magnetic fields and…

Mesoscale and Nanoscale Physics · Physics 2017-02-08 Wister Huang , Menno Veldhorst , Neil M. Zimmerman , Andrew S. Dzurak , Dimitrie Culcer

State-of-the-art superconducting quantum processors containing tens to hundreds of qubits have demonstrated the building blocks for realizing fault-tolerant quantum computation. Nonetheless, a fundamental barrier to scaling further is the…

The presence of valley states is a significant obstacle to realizing quantum information technologies in Silicon quantum dots, as leakage into alternate valley states can introduce errors into the computation. We use a perturbative…

Mesoscale and Nanoscale Physics · Physics 2022-01-25 Donovan Buterakos , Sankar Das Sarma

Strain is extensively used to controllably tailor the electronic properties of materials. In the context of indirect band-gap semiconductors such as silicon, strain lifts the valley degeneracy of the six conduction band minima, and by…

We develop a valley-dependent envelope function theory that can describe the effects of arbitrary configurations of interface steps and miscuts on the qubit relaxation time. For a given interface roughness, we show how our theory can be…

Mesoscale and Nanoscale Physics · Physics 2021-09-01 Amin Hosseinkhani , Guido Burkard

Quantum dots in silicon are promising candidates for implementation of solid-state quantum information processing. It is important to understand the effects of the multiple conduction band valleys of silicon on the properties of these…

Mesoscale and Nanoscale Physics · Physics 2013-08-27 John King Gamble , M. A. Eriksson , S. N. Coppersmith , Mark Friesen

A detailed understanding of the material properties that affect the splitting between the two low-lying valley states in Si/SiGe heterostructures will be increasingly important as the number of spin qubits is increased. Scanning gate…

Mesoscale and Nanoscale Physics · Physics 2024-10-04 Efe Cakar , H. Ekmel Ercan , Gordian Fuchs , Artem O. Denisov , Christopher R. Anderson , Mark F. Gyure , Jason R. Petta

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…