Extended interface states enhance valley splitting in Si/SiO2

Abstract

Interface disorder and its effect on the valley degeneracy of the conduction band edge remains among the greatest theoretical challenges for understanding the operation of spin qubits in silicon. Here, we investigate a counterintuitive effect occurring at Si/SiO2 interfaces. By applying tight binding methods, we show that intrinsic interface states can hybridize with conventional valley states, leading to a large ground state energy gap. The effects of hybridization have not previously been explored in details for valley splitting. We find that valley splitting is enhanced in the presence of disordered chemical bonds, in agreement with recent experiments.

4 pages, 4 figures

References in corpus (9)

• Exchange in silicon-based quantum computer architecture
• Controllable valley splitting in silicon quantum devices
• Design and proof of concept for silicon-based quantum dot quantum bits
• Practical design and simulation of silicon-based quantum dot qubits
• Valley splitting in strained silicon quantum wells
• Valley Polarization in Si(100) at Zero Magnetic Field
• Physical mechanisms of interface-mediated intervalley coupling in Si
• Interface roughness, valley-orbit coupling and valley manipulation in quantum dots
• Magnetic field dependence of valley splitting in realistic Si/SiGe quantum wells

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• Practical Strategies for Enhancing the Valley Splitting in Si/SiGe Quantum Wells
• Detection of a large valley-orbit splitting in silicon with two-donor spectroscopy
• Disorder-induced valley-orbit hybrid states in Si quantum dots
• Spin filling of valley-orbit states in a silicon quantum dot
• Hybrid spin and valley quantum computing with singlet-triplet qubits
• Engineered valley-orbit splittings in quantum confined nanostructures in silicon
• Valley polarization assisted spin polarization in two dimensions
• Electromagnetic control of valley splitting in ideal and disordered Si quantum dots
• Electric field reduced charging energies and two-electron bound excited states of single donors in silicon
• Signatures of atomic-scale structure in the energy dispersion and coherence of a Si quantum-dot qubit
• Coherent electrical rotations of valley states in Si quantum dots using the phase of the valley-orbit coupling
• Splitting Valleys in Si/SiO${}_2$: Identification and Control of Interface States
• Valley splitting by extended zone effective mass approximation incorporating strain in silicon