Orbital and valley state spectra of a few-electron silicon quantum dot

Abstract

Understanding interactions between orbital and valley quantum states in silicon nanodevices is crucial in assessing the prospects of spin-based qubits. We study the energy spectra of a few-electron silicon metal-oxide-semiconductor quantum dot using dynamic charge sensing and pulsed-voltage spectroscopy. The occupancy of the quantum dot is probed down to the single-electron level using a nearby single-electron transistor as a charge sensor. The energy of the first orbital excited state is found to decrease rapidly as the electron occupancy increases from N=1 to 4. By monitoring the sequential spin filling of the dot we extract a valley splitting of ~230 μeV, irrespective of electron number. This indicates that favorable conditions for qubit operation are in place in the few-electron regime.

4 figures

References in corpus (4)

• Electron spin decoherence in isotope-enriched silicon
• Excited-state spectroscopy on a nearly-closed quantum dot via charge detection
• Measurement of valley splitting in high-symmetry Si/SiGe quantum dots
• Spin filling of valley-orbit states in a silicon quantum dot

Cited by in corpus (14)

• Scalable gate architecture for densely packed semiconductor spin qubits
• A Reconfigurable Gate Architecture for Si/SiGe Quantum Dots
• High-fidelity operation and algorithmic initialisation of spin qubits above one kelvin
• SiGe quantum wells with oscillating Ge concentrations for quantum dot qubits
• Dispersive readout of valley splittings in cavity-coupled silicon quantum dots
• On-demand electrical control of spin qubits
• Modelling semiconductor spin qubits and their charge noise environment for quantum gate fidelity estimation
• Charge State Hysteresis in Semiconductor Quantum Dots
• Bounds to electron spin qubit variability for scalable CMOS architectures
• Optimal control of a cavity-mediated iSWAP gate between silicon spin qubits
• High temperature spin selectivity in a quantum dot qubit using reservoir spin accumulation
• Singlet-triplet-state readout in silicon-metal-oxide-semiconductor double quantum dots
• Latched readout for the quantum dot hybrid qubit
• A 2x2 quantum dot array in silicon with fully tuneable pairwise interdot coupling