Valley Kondo Effect in Silicon Quantum Dots

Abstract

Recent progress in the fabrication of quantum dots using silicon opens the prospect of observing the Kondo effect associated with the valley degree of freedom. We compute the dot density of states using an Anderson model with infinite Coulomb interaction $U$, whose structure mimics the nonlinear conductance through a dot. The density of states is obtained as a function of temperature and applied magnetic field in the Kondo regime using an equation-of-motion approach. We show that there is a very complex peak structure near the Fermi energy, with several signatures that distinguish this spin-valley Kondo effect from the usual spin Kondo effect seen in GaAs dots. We also show that the valley index is generally not conserved when electrons tunnel into a silicon dot, though the extent of this non-conservation is expected to be sample-dependent. We identify features of the conductance that should enable experimenters to understand the interplay of Zeeman splitting and valley splitting, as well as the dependence of tunneling on the valley degree of freedom.

References in corpus (7)

• Orbital Kondo effect in carbon nanotubes
• Controllable valley splitting in silicon quantum devices
• Valley Splitting Theory of SiGe/Si/SiGe Quantum Wells
• On the applicability of the equations-of-motion technique for quantum dots
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Cited by in corpus (12)

• Silicon Quantum Electronics
• Magnetic Field Probing of an SU(4) Kondo Resonance in a Single Atom Transistor
• Disorder-induced valley-orbit hybrid states in Si quantum dots
• Tunable Spin Qubit Coupling Mediated by a Multi-Electron Quantum Dot
• Tunable Kondo effect in a single donor atom
• Probing the Spatial Variation of the Inter-Valley Tunnel Coupling in a Silicon Triple Quantum Dot
• Signatures of atomic-scale structure in the energy dispersion and coherence of a Si quantum-dot qubit
• Kondo screening of Andreev bound states in an N-QD-S system
• Valley Phase and Voltage Control of Coherent Manipulation in Si Quantum Dots
• Valley blockade and multielectron spin-valley Kondo effect in silicon
• Spin-Valley Kondo Effect in Multi-electron Silicon Quantum Dots
• Signatures of Valley Kondo Effect in Si/SiGe Quantum Dots