Detuning Axis Pulsed Spectroscopy of Valley-Orbital States in Si/SiGe Quantum Dots

Abstract

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 device performance. We describe a spectroscopic method for probing excited states in isolated Si/SiGe double quantum dots using standard baseband pulsing techniques, easing the extraction of energy spectra in multiple-dot devices. We use this method to measure dozens of valley excited state energies spanning multiple wafers, quantum dots, and orbital states, crucial for evaluating the dependence of valley splitting on quantum well width and other epitaxial conditions. Our results suggest that narrower wells can be beneficial for improving valley splittings, but this effect can be confounded by variations in growth and fabrication conditions. These results underscore the importance of valley splitting measurements for guiding the development of Si qubits.

arXiv comment13 pages, 12 figures. accepted for publication by Physical Review Applied

References in corpus (36)

• Silicon Quantum Electronics
• Universal Quantum Computation with the Exchange Interaction
• Manipulation of a single charge in a double quantum dot
• Reduced sensitivity to charge noise in semiconductor spin qubits via symmetric operation
• Controllable valley splitting in silicon quantum devices
• Valley Splitting Theory of SiGe/Si/SiGe Quantum Wells
• Model for the on-site matrix elements of the tight-binding hamiltonian of a strained crystal: Application to silicon, germanium and their alloys
• Tunable spin-selective loading of a silicon spin qubit
• Valley splitting in strained silicon quantum wells
• Coherent Quantum Oscillations in a Silicon Charge Qubit
• Excited-state spectroscopy on a nearly-closed quantum dot via charge detection
• Electrically Protected Valley-Orbit Qubits in Silicon
• Measurement of valley splitting in high-symmetry Si/SiGe quantum dots
• Pauli Blockade in Silicon Quantum Dots with Spin-Orbit Control
• Large, tunable valley splitting and single-spin relaxation mechanisms in a Si/Si${}_x$Ge${}_{1-x}$ quantum dot
• Pauli spin blockade in undoped Si/SiGe two-electron double quantum dots
• High Resolution Valley Spectroscopy of Si Quantum Dots
• Charge Relaxation in a Single Electron Si/SiGe Double Quantum Dot
• Relaxation of excited spin, orbital, and valley qubit states in single electron silicon quantum dots
• Electric field effect on electron spin splitting in SiGe/Si quantum wells
• Quantifying error and leakage in an encoded Si/SiGe triple-dot qubit
• Quantum dot spin qubits in Silicon: Multivalley physics
• Genetic Design of Enhanced Valley Splitting towards a Spin Qubit in Silicon
• Valley splitting of single-electron Si MOS quantum dots
• Disorder-induced valley-orbit hybrid states in Si quantum dots
• Tetragonal and trigonal deformations in zinc-blende semiconductors : a tight-binding point of view
• Qubit relaxation from evanescent-wave Johnson noise
• The critical role of substrate disorder in valley splitting in Si quantum wells
• Spin-Blockade Spectroscopy of Si/SiGe Quantum Dots
• Magnetic Gradient Fluctuations from Quadrupolar ${}^{73}$Ge in Si/SiGe Exchange-Only Qubits
• Electron tunnel rates in a donor-silicon single electron transistor hybrid
• Effects of Interface Disorder on Valley Splitting in SiGe/Si/SiGe Quantum Wells
• Valley Phase and Voltage Control of Coherent Manipulation in Si Quantum Dots
• Effect of quantum Hall edge strips on valley splitting in silicon quantum wells
• Well-width dependence of valley splitting in Si/SiGe quantum wells
• Radio frequency pulsed-gate charge spectroscopy on coupled quantum dots

Cited by in corpus (33)

• Semiconductor Spin Qubits
• Review of performance metrics of spin qubits in gated semiconducting nanostructures
• Universal logic with encoded spin qubits in silicon
• Practical Strategies for Enhancing the Valley Splitting in Si/SiGe Quantum Wells
• Fast and high-fidelity state preparation and measurement in triple-quantum-dot spin qubits
• Strong electron-electron interactions in Si/SiGe quantum dots
• Coherent control and spectroscopy of a semiconductor quantum dot Wigner molecule
• Low disorder and high valley splitting in silicon
• How valley-orbit states in silicon quantum dots probe quantum well interfaces
• Coherent spin-valley oscillations in silicon
• Mapping of valley-splitting by conveyor-mode spin-coherent electron shuttling
• Probing the Spatial Variation of the Inter-Valley Tunnel Coupling in a Silicon Triple Quantum Dot
• Utilizing multimodal microscopy to reconstruct Si/SiGe interfacial atomic disorder and infer its impacts on qubit variability
• Wafer-scale low-disorder 2DEG in ${}^{28}$Si/SiGe without an epitaxial Si cap
• Interface and electromagnetic effects in the valley splitting of Si quantum dots
• Cryogen-free scanning gate microscope for the characterization of Si/Si${}_{0.7}$Ge${}_{0.3}$ quantum devices at milli-Kelvin temperatures
• Coherent control of a triangular exchange-only spin qubit
• Microwave-frequency scanning gate microscopy of a Si/SiGe double quantum dot
• Coupling conduction-band valleys in SiGe heterostructures via shear strain and Ge concentration oscillations
• Atomistic compositional details and their importance for spin qubits in isotope-purified silicon-germanium quantum wells
• Measurement of tunnel coupling in a Si double quantum dot based on charge sensing
• Valley-Free Silicon Fins Caused by Shear Strain
• Valley splitting depending on the size and location of a silicon quantum dot
• Optimal control of a cavity-mediated iSWAP gate between silicon spin qubits
• Local laser-induced solid-phase recrystallization of phosphorus-implanted Si/SiGe heterostructures for contacts below 4.2 K
• Gate reflectometry in dense quantum dot arrays
• Charge-noise resilience of two-electron quantum dots in Si/SiGe heterostructures
• Dissipation and gate timing errors in SWAP operations of qubits
• Valley Splitting Correlations Across a Silicon Quantum Well Containing Germanium
• Proposal for a cavity-induced measurement of the exchange coupling in quantum dots
• The effects of alloy disorder on strongly-driven flopping mode qubits in Si/SiGe
• Towards Utilizing Scanning Gate Microscopy as a High-Resolution Probe of Valley Splitting in Si/SiGe Heterostructures
• Measuring and correcting nanosecond pulse distortions in quantum-dot spin qubits