Valley splitting of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">Si</mml:mi><mml:mo>∕</mml:mo><mml:msub><mml:mi mathvariant="normal">Si</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">Ge</mml:mi><mml:mi>x</mml:mi></mml:msub></mml:mrow></mml:math>heterostructures in tilted magnetic fields

Lai, Keji; Lu, Tzu-Ming; Pan, W.; Tsui, D. C.; Lyon, Stephen; Liu, J.; Xie, Ya‐Hong; Mühlberger, M.; Schäffler, F.

doi:10.1103/physrevb.73.161301

Cited by 31 publications

(33 citation statements)

References 21 publications

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“…This is different from the transport features in a square sample without Hall bar pattern. This transport feature has been observed before [51,52,53] in GaAs/AlGaAs single heterojunctions and in AlAs, and Si/SiGe quantum wells. A spin-filtering mechanism based on spin Hall effect was proposed in Li's thesis [51], which we will adopt in this report.…”

Section: Spin-filtering Phenomenon In Long Narrow Hall Bar Devicesupporting

confidence: 61%

Understanding the physics of a possible non-Abelian fractional quantum hall effect state.

Pan¹,

Crawford²,

Tallakulam³

et al. 2010

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We wish to present in this report experimental results from a one-year Senior Council Tier-1 LDRD project that focused on understanding the physics of a possible nonAbelian fractional quantum Hall effect state. We first give a general introduction to the quantum Hall effect, and then present the experimental results on the edge-state transport in a special fractional quantum Hall effect state at Landau level filling =5/2 -a possible non-Abelian quantum Hall state. This state has been at the center of current basic research due to its potential applications in fault-resistant topological quantum computation. We will also describe the semiconductor "Hall-bar" devices we used in this project. 4 5

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Section: Spin-filtering Phenomenon In Long Narrow Hall Bar Devicesupporting

confidence: 61%

Understanding the physics of a possible non-Abelian fractional quantum hall effect state.

Pan¹,

Crawford²,

Tallakulam³

et al. 2010

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“…72 ∆ is generally not known a priori, is sampledependent, 73 and is different for different interfaces, such as Si/SiGe and Si/SiO 2 . Various measurements of ∆ have been reported, 67,[74][75][76] and efforts have been devoted to calculating ∆. 54,73,[77][78][79][80][81] Yet the fact that ∆ is not known and no standard experiment exists to measure it in a QD at low field is a strong motivating factor for our work.…”

Section: 52mentioning

confidence: 99%

Quantum dot spin qubits in silicon: Multivalley physics

Culcer

Cywiński²,

Li³

et al. 2010

Phys. Rev. B

158

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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 interface potential, which gives rise to a valley-orbit coupling, but the latter depends on the detailed structure of the interface and is generally unknown a priori. These facts motivate us to provide an extensive study of spin qubits in Si double quantum dots, accounting fully for the valley degree of freedom and assuming no prior knowledge of the valleyorbit coupling. For single-spin qubits we analyze the spectrum of a multivalley double quantum dot, discuss the initialization of one qubit, identify the conditions for the lowest energy two-electron states to be a singlet and a triplet well separated from other states, and determine analytical expressions for the exchange splitting. For singlet-triplet qubits we analyze the single-dot spectrum and initialization process, the double-dot spectrum, singlet-triplet mixing in an inhomogeneous magnetic field and the peculiarities of spin blockade in multivalley qubits. We review briefly the hyperfine interaction in Si and discuss its role in spin blockade in natural Si, including intravalley and intervalley effects. We study the evolution of the double-dot spectrum as a function of magnetic field. We address briefly the situation in which the valley-orbit coupling is different in each dot due to interface roughness. We propose a new experiment for measuring the valley splitting in a single quantum dot. We discuss the possibility of devising other types of qubits in Si QDs, and the size of the intervaley coupling due to the Coulomb interaction.

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“…Finally, we expect that spin dependent resistivity in the QHE regime should be present in other 2D carrier systems; indeed, it has recently been reported in the Si/SiGe 2DESs. 32 …”

Section: Spin-dependent Resistivity At Transitions Between Qhe Statesmentioning

confidence: 99%

Two‐dimensional electrons occupying multiple valleys in AlAs

Shayegan

Poortere

Gunawan

et al. 2006

Physica Status Solidi (b)

131

202

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Two-dimensional electrons in AlAs quantum wells occupy multiple conduction-band minima at the Xpoints of the Brillouin zone. These valleys have large effective mass and g-factor compared to the standard GaAs electrons, and are also highly anisotropic. With proper choice of well width and by applying symmetry-breaking strain in the plane, one can control the occupation of different valleys thus rendering a system with tuneable effective mass, g-factor, Fermi contour anisotropy, and valley degeneracy. Here we review some of the rich physics that this system has allowed us to explore.

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Valley splitting ofSi∕Si1−xGexheterostructures in tilted magnetic fields

Cited by 31 publications

References 21 publications

Understanding the physics of a possible non-Abelian fractional quantum hall effect state.

Understanding the physics of a possible non-Abelian fractional quantum hall effect state.

Quantum dot spin qubits in silicon: Multivalley physics

Two‐dimensional electrons occupying multiple valleys in AlAs

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