Tunable singlet-triplet splitting in a few-electron Si/SiGe quantum dot

Abstract

We measure the excited-state spectrum of a Si/SiGe quantum dot as a function of in-plane magnetic field, and we identify the spin of the lowest three eigenstates in an effective two-electron regime. The singlet-triplet splitting is an essential parameter describing spin qubits, and we extract this splitting from the data. We find it to be tunable by lateral displacement of the dot, which is realized by changing two gate voltages on opposite sides of the device. We present calculations showing the data are consistent with a spectrum in which the first excited state of the dot is a valley-orbit state.

4 pages with 3 figures

References in corpus (8)

• Pauli-Spin-Blockade Transport through a Silicon Double Quantum Dot
• Excited-state spectroscopy on a nearly-closed quantum dot via charge detection
• Measurement of valley splitting in high-symmetry Si/SiGe quantum dots
• Magnetic field dependence of valley splitting in realistic Si/SiGe quantum wells
• Single-electron quantum dot in Si/SiGe with integrated charge-sensing
• Spin filling of valley-orbit states in a silicon quantum dot
• Fast tunnel rates in Si/SiGe one-electron single and double quantum dots
• Extended interface states enhance valley splitting in Si/SiO2

Cited by in corpus (52)

• Silicon Quantum Electronics
• Prospects for Spin-Based Quantum Computing
• A fast "hybrid" silicon double quantum dot qubit
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• Quantum Decoherence of the Central Spin in a Sparse System of Dipolar Coupled Spins
• Fast coherent manipulation of three-electron states in a double quantum dot
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• Extending the coherence of a quantum dot hybrid qubit
• Large, tunable valley splitting and single-spin relaxation mechanisms in a Si/Si${}_x$Ge${}_{1-x}$ quantum dot
• Pulse-gated quantum dot hybrid qubit
• Atomic fluctuations lifting the energy degeneracy in Si/SiGe quantum dots
• Blueprint of a scalable spin qubit shuttle device for coherent mid-range qubit transfer in disordered Si/SiGe/SiO${}_2$
• SiGe quantum wells with oscillating Ge concentrations for quantum dot qubits
• Practical Strategies for Enhancing the Valley Splitting in Si/SiGe Quantum Wells
• Dispersive readout of valley splittings in cavity-coupled silicon quantum dots
• Valley splitting of single-electron Si MOS quantum dots
• Disorder-induced valley-orbit hybrid states in Si quantum dots
• Valley splittings in Si/SiGe quantum dots with a germanium spike in the silicon well
• Low disorder and high valley splitting in silicon
• High-fidelity gates in quantum dot spin qubits
• Two-electron dephasing in single Si and GaAs quantum dots
• The critical role of substrate disorder in valley splitting in Si quantum wells
• A quadrupolar exchange-only spin qubit
• How valley-orbit states in silicon quantum dots probe quantum well interfaces
• First-Principles Prediction of Electronic Transport in Experimental Semiconductor Heterostructures via Physics-Based Machine Learning
• Mapping of valley-splitting by conveyor-mode spin-coherent electron shuttling
• Spin-Blockade Spectroscopy of Si/SiGe Quantum Dots
• Noise-compensating pulses for electrostatically controlled silicon spin qubits
• Strategies for enhancing spin-shuttling fidelities in Si/SiGe quantum wells with random-alloy disorder
• Signatures of atomic-scale structure in the energy dispersion and coherence of a Si quantum-dot qubit
• Interface and electromagnetic effects in the valley splitting of Si quantum dots
• Valley Phase and Voltage Control of Coherent Manipulation in Si Quantum Dots
• SiGe/Si quantum dot electron spin decoherence dependence on ${}^{73}$Ge
• Transport through an impurity tunnel coupled to a Si/SiGe quantum dot
• Effect of quantum Hall edge strips on valley splitting in silicon quantum wells
• Voltage controlled exchange energies of a two electron silicon double quantum dot with and without charge defects in the dielectric
• Valley-Free Silicon Fins Caused by Shear Strain
• Atomistic compositional details and their importance for spin qubits in isotope-purified silicon-germanium quantum wells
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• Characterization of a gate-defined double quantum dot in a Si/SiGe nanomembrane
• Theoretical Prediction of Enhanced Thermopower in n-doped Si/Ge Superlattices using Effective Mass Approximation
• Charge noise suppression in capacitively coupled singlet-triplet spin qubits under magnetic field
• Phonon-induced decoherence of a charge quadrupole qubit
• Long-range two-hybrid-qubit gates mediated by a microwave cavity with red sidebands
• Coherence of a field-gradient-driven singlet-triplet qubit coupled to many-electron spin states in 28Si/SiGe
• Robust entangling gate for capacitively coupled few-electron singlet-triplet qubits
• Spin relaxation of a donor electron coupled to interface states
• Sign-switching of superexchange mediated by few electrons under non-uniform magnetic field
• Modulation of Semiconductor Superlattice Thermopower Through Symmetry and Strain
• The effects of alloy disorder on strongly-driven flopping mode qubits in Si/SiGe
• Micromagnet-free operation of electron spin qubits in Si/Si${}_{1-x}$Ge${}_x$ vertical double quantum dots