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Related papers: Valley interference effects on a donor electron cl…

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The presence of non-degenerate valley states in silicon can drastically affect electron dynamics in silicon-based heterostructures, leading to electron spin relaxation and spin-valley coupling. In the context of solid-state spin qubits, it…

Mesoscale and Nanoscale Physics · Physics 2020-11-18 Nicholas E. Penthorn , Joshua S. Schoenfield , Lisa F. Edge , HongWen Jiang

We consider charge qubits based on shallow donor electron states in silicon and coupled quantum dots in GaAs. Specifically, we study the feasibility of P$_2^+$ charge qubits in Si, focusing on single qubit properties in terms of tunnel…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Xuedong Hu , Belita Koiller , S. Das Sarma

Interface states in a silicon/barrier junction break the silicon valley degeneracy near the interface, a desirable feature for some Si quantum electronics applications. Within a minimal multivalley tight-binding model in one dimension, we…

Mesoscale and Nanoscale Physics · Physics 2014-05-23 Amintor Dusko , A. L. Saraiva , Belita Koiller

Electron states are studied for quantum dots in a strained Si quantum well, taking into account both valley and orbital physics. Realistic geometries are considered, including circular and elliptical dot shapes, parallel and perpendicular…

Mesoscale and Nanoscale Physics · Physics 2015-03-13 Mark Friesen , S. N. Coppersmith

We develop a theory of Coulomb interaction-related contribution to the photogalvanic current of the carriers of charge in two-dimensional non-centrosymmetric Dirac materials possessing a nontrivial structure of valleys and exposed to an…

Mesoscale and Nanoscale Physics · Physics 2024-06-13 V. M. Kovalev , A. V. Parafilo , O. V. Kibis , I. G. Savenko

Electrons confined in silicon quantum dots exhibit orbital, spin, and valley degrees of freedom. The valley degree of freedom originates from the bulk bandstructure of silicon, which has six degenerate electronic minima. The degeneracy can…

Mesoscale and Nanoscale Physics · Physics 2021-05-05 F. Borjans , X. Zhang , X. Mi , G. Cheng , N. Yao , C. A. C. Jackson , L. F. Edge , J. R. Petta

Donors in silicon are now demonstrated as one of the leading candidates for implementing qubits and quantum information processing. Single qubit operations, measurements and long coherence times are firmly established, but progress on…

Mesoscale and Nanoscale Physics · Physics 2014-07-09 G. Pica , B. W. Lovett , R. N Bhatt , S. A. Lyon

The valley splitting of 2D electrons in doubly-gated silicon-on-insulator quantum wells is studied by low temperature transport measurements under magnetic fields. At the buried thermal-oxide SiO$_{2}$ interface, the valley splitting…

Mesoscale and Nanoscale Physics · Physics 2025-09-03 Nathan Aubergier , Vincent T. Renard , Sylvain Barraud , Kei Takashina , Benjamin A. Piot

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

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…

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

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

Coherent coupling between distant qubits is needed for any scalable quantum computing scheme. In quantum dot systems, one proposal for long-distance coupling is to coherently transfer electron spins across a chip in a moving potential.…

The authors investigate the magnetic field dependence of the energy splitting between low-lying valley states for electrons in a Si/SiGe quantum well tilted with respect to the crystallographic axis. The presence of atomic steps at the…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Mark Friesen , M. A. Eriksson , S. N. Coppersmith

We report measurements consistent with the valley Kondo effect in Si/SiGe quantum dots, evidenced by peaks in the conductance versus source-drain voltage that show strong temperature dependence. The Kondo peaks show unusual behavior in a…

Mesoscale and Nanoscale Physics · Physics 2014-07-04 Mingyun Yuan , R. Joynt , Zhen Yang , Chunyang Tang , D. E. Savage , M. G. Lagally , M. A. Eriksson , A. J. Rimberg

Spin qubits hosted in silicon (Si) quantum dots (QD) are attractive due to their exceptionally long coherence times and compatibility with the silicon transistor platform. To achieve electrical control of spins for qubit scalability, recent…

We experimentally investigate electron transport through the interface between a superconductor and the edge of a two-dimensional electron system with band inversion. The interface is realized as a tunnel NbN side contact to a narrow 8~nm…

Mesoscale and Nanoscale Physics · Physics 2015-06-23 A. Kononov , S. V. Egorov , N. Titova , Z. D. Kvon , N. N. Mikhailov , S. A. Dvoretsky , E. V. Deviatov

Understanding strongly interacting electrons enables the design of materials, nanostructures and devices. Developing this understanding relies on the ability to tune and control electron-electron interactions by, e.g., confining electrons…

Strongly Correlated Electrons · Physics 2021-01-04 Ludmila Szulakowska , Moritz Cygorek , Maciej Bieniek , Pawel Hawrylak

We propose a geometric phase-resolved tunneling valley Hall effect based on the coherent transmission through two combined electric barriers in $\alpha-\mathcal{T}_3$ lattices. It is shown that the backreflected electrons at the barrier…

Mesoscale and Nanoscale Physics · Physics 2024-11-07 W. Zeng

Inter-valley interference between degenerate conduction band minima has been shown to lead to oscillations in the exchange energy between neighbouring phosphorus donor electron states in silicon \cite{Koiller02,Koiller02A}. These same…