Microwave-frequency scanning gate microscopy of a Si/SiGe double quantum dot

Abstract

Conventional quantum transport methods can provide quantitative information on spin, orbital, and valley states in quantum dots, but often lack spatial resolution. Scanning tunneling microscopy, on the other hand, provides exquisite spatial resolution of the local electronic density of states, but often at the expense of speed. Working to combine the spatial resolution and energy sensitivity of scanning probe microscopy with the speed of microwave measurements, we couple a metallic probe tip to a Si/SiGe double quantum dot that is integrated with a local charge detector. We first demonstrate that a dc-biased tip can be used to change the charge occupancy of the double dot. We then apply microwave excitation through the scanning tip to drive photon-assisted tunneling transitions in the double dot. We infer the double dot energy level diagram from the frequency and detuning dependence of the photon-assisted tunneling resonance condition. These measurements allow us to resolve $\sim$65 $\mu$eV excited states, an energy scale consistent with typical valley splittings in Si/SiGe. Future extensions of this approach may allow spatial mapping of the valley splitting in Si devices, which is of fundamental importance for spin-based quantum processors.

References in corpus (34)

• Quantum Computation with Quantum Dots
• Spins in few-electron quantum dots
• Electron transport through double quantum dots
• Silicon Quantum Electronics
• Semiconductor Spin Qubits
• Electron spin coherence exceeding seconds in high purity silicon
• Quantum CNOT Gate for Spins in Silicon
• Computing with spin qubits at the surface code error threshold
• Fast universal quantum control above the fault-tolerance threshold in silicon
• Manipulation of a single charge in a double quantum dot
• Quantum Coherence in a One-Electron Semiconductor Charge Qubit
• Two-qubit silicon quantum processor with operation fidelity exceeding 99%
• Scalable gate architecture for densely packed semiconductor spin qubits
• Controllable valley splitting in silicon quantum devices
• Universal logic with encoded spin qubits in silicon
• A double-dot quantum ratchet driven by an independently biased quantum point contact
• Theory of valley-orbit coupling in a Si/SiGe quantum dot
• Spatially resolved manipulation of single electrons in quantum dots using a scanned probe
• Interface roughness, valley-orbit coupling and valley manipulation in quantum dots
• High Resolution Valley Spectroscopy of Si Quantum Dots
• Charge Relaxation in a Single Electron Si/SiGe Double Quantum Dot
• Imaging a Single-Electron Quantum Dot
• Quenching of dynamic nuclear polarization by spin-orbit coupling in GaAs quantum dots
• Single-Spin Relaxation in a Synthetic Spin-Orbit Field
• Detuning Axis Pulsed Spectroscopy of Valley-Orbital States in Si/SiGe Quantum Dots
• Imaging a 1-electron InAs quantum dot in an InAs/InP nanowire
• How valley-orbit states in silicon quantum dots probe quantum well interfaces
• Quantum state readout of individual quantum dots by electrostatic force detection
• Effects of Interface Steps on the Valley Orbit coupling in a Si/SiGe quantum dot
• Probing the Spatial Variation of the Inter-Valley Tunnel Coupling in a Silicon Triple Quantum Dot
• Imaging a Coupled Quantum Dot - Quantum Point Contact System
• Spatial mapping and manipulation of two tunnel-coupled quantum dots
• Cryogen-free scanning gate microscope for the characterization of Si/Si${}_{0.7}$Ge${}_{0.3}$ quantum devices at milli-Kelvin temperatures
• Spin-Valley Qubit Dynamics In Exchange Coupled Silicon Quantum Dots

Cited by in corpus (10)

• Mapping of valley-splitting by conveyor-mode spin-coherent electron shuttling
• Microwave power harvesting using resonator-coupled double quantum dot photodiode
• Valley-Free Silicon Fins Caused by Shear Strain
• Valleytronic full configuration-interaction approach: An application to the excitation spectra of Si double-dot qubits
• In-situ scanning gate imaging of individual two-level material defects in live superconducting quantum circuits
• Dispersive readout of a silicon quantum device using an atomic force microscope-based rf gate sensor
• Second Quantization: Gating a Quantum Dot Through the Sequential Removal of Single Electrons from a Nanoscale Floating Gate
• Towards Utilizing Scanning Gate Microscopy as a High-Resolution Probe of Valley Splitting in Si/SiGe Heterostructures
• Supercurrent modulation in InSb nanoflag-based Josephson junctions by scanning gate microscopy
• Signatures of Majorana bound states in scanning gate microscopy of hybrid nanowires