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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

With any roughness at the interface of an indirect-bandgap semiconducting dot, the phase of the valley-orbit coupling can take on a random value. This random value, in double quantum dots, causes a large change in the exchange splitting. We…

Mesoscale and Nanoscale Physics · Physics 2017-12-11 Neil Zimmerman , Peihao Huang , Dimitrie Culcer

A gate electric field has a small but non-negligible effect on the phase of the valley-orbit coupling in Si quantum dots. Finite interdot tunneling between valley eigenstates in a double quantum dot is enabled by a small difference in the…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 Yue Wu , Dimitrie Culcer

Understanding interactions between orbital and valley quantum states in silicon nanodevices is crucial in assessing the prospects of spin-based qubits. We study the energy spectra of a few-electron silicon metal-oxide-semiconductor quantum…

Mesoscale and Nanoscale Physics · Physics 2012-10-12 C. H. Yang , W. H. Lim , N. S. Lai , A. Rossi , A. Morello , A. S. Dzurak

The presence of degenerate conduction band valleys and how they are mixed by interfaces play critical roles in determining electron interaction and spectrum in a silicon nanostructure. Here we investigate how the valley phases affect the…

Mesoscale and Nanoscale Physics · Physics 2021-07-05 Bilal Tariq , Xuedong Hu

Silicon quantum dot qubits must contend with low-lying valley excited states which are sensitive functions of the quantum well heterostructure and disorder; quantifying and maximizing the energies of these states are critical to improving…

Recent experiments on silicon nanostructures have seen breakthroughs toward scalable, long-lived quantum information processing. The valley degree of freedom plays a fundamental role in these devices, and the two lowest-energy electronic…

Mesoscale and Nanoscale Physics · Physics 2016-07-27 Péter Boross , Gábor Széchenyi , Dimitrie Culcer , András Pályi

Interactions between electrons can strongly affect the shape and functionality of multi-electron quantum dots. The resulting charge distributions can be localized, as in the case of Wigner molecules, with consequences for the energy…

Mesoscale and Nanoscale Physics · Physics 2021-12-14 H. Ekmel Ercan , S. N. Coppersmith , Mark Friesen

The energy spectrum and wave functions of electrons in a single silicon quantum dot provide valuable insights into the capabilities and limitations of such a system in quantum information processing. Here we investigate the low-lying…

Mesoscale and Nanoscale Physics · Physics 2026-03-26 Bilal Tariq , Xuedong Hu

Valley-orbit coupling is a key parameter for a silicon quantum dot in determining its suitability for applications in quantum information processing. In this paper we study the effect of interface steps on the magnitude and phase of…

Mesoscale and Nanoscale Physics · Physics 2019-10-02 Bilal Tariq , Xuedong Hu

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

Silicon-based metal-oxide-semiconductor quantum dots are prominent candidates for high-fidelity, manufacturable qubits. Due to silicon's band structure, additional low-energy states persist in these devices, presenting both challenges and…

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

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

An important challenge in silicon quantum electronics in the few electron regime is the potentially small energy gap between the ground and excited orbital states in 3D quantum confined nanostructures due to the multiple valley degeneracies…

Mesoscale and Nanoscale Physics · Physics 2011-05-30 R. Rahman , J. Verduijn , N. Kharche , G. P. Lansbergen , G. Klimeck , L. C. L. Hollenberg , S. Rogge

In this paper, we studied the inter-valley interactions between the orbital functions associated with multi-valley of silicon (Si) quantum dots. Numerical calculations show that the inter-valley coupling between orbital functions increases…

Quantum Physics · Physics 2009-11-10 Doyeol Ahn

Electronic states in silicon quantum dots are examined theoretically, taking into account a multivalley structure of the conduction band. We find that (i) exchange interaction hardly works between electrons in different valleys. In…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Yoko Hada , Mikio Eto

We present a systematic study of interface roughness and its effect on coherent dynamical processes in quantum dots. The potential due to a sharp, flat interface lifts the degeneracy of the lowest energy valleys and yields a set of valley…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 Dimitrie Culcer , Xuedong Hu , S. Das Sarma

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

We study single and double quantum dots defined electrostatically within silicene. The spin-valley structure of the confined single- and two-electron system is determined and the effects of the intervalley scattering induced by the crystal…

Mesoscale and Nanoscale Physics · Physics 2018-10-17 B. Szafran , D. Zebrowski
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