GHz operation of a quantum point contact using stub impedance matching circuit
arXiv:2311.13804 · doi:10.1016/j.physo.2023.100181
Abstract
Quantum point contacts (QPC) are the building blocks of quantum dot qubits and semiconducting quantum electrical metrology circuits. QPCs also make highly sensitive electrical amplifiers with the potential to operate in the quantum-limited regime. Though the inherent operational bandwidth of QPCs can eclipse the THz regime, the impedance mismatch with the external circuitry limits the operation to a few kHz regimes. Lumped-element impedance-matching circuits are successful only up to a few hundreds of MHz. QPCs are characterised by a complex impedance consisting of quantized resistance, capacitance, and inductance elements. Characterising the complex admittance at higher frequencies and understanding the coupling of QPC to other circuit elements and electromagnetic environments will provide valuable insight into its sensing and backaction properties. In this work, we couple a QPC galvanically to a superconducting stub tuner impedance matching circuit realised in a coplanar waveguide architecture to enhance the operation frequency into the GHz regime and investigate the electrical amplification and complex admittance characteristics. The device, operating at 1.96 GHz exhibits a conductance sensitivity of 29.2 micro-e/SQRT(Hz) and a bandwidth of 13MHz. Besides, the RF reflected power unambiguously reveals the complex admittance characteristics of the QPC, shining more light on the behaviour of quantum tunnel junctions at higher operational frequencies.
References in corpus (20)
- Quantum Computation with Quantum Dots
- Spins in few-electron quantum dots
- Coherent control of macroscopic quantum states in a single-Cooper-pair box
- Electron transport through double quantum dots
- Single-shot read-out of an individual electron spin in a quantum dot
- Circuit Quantum Electrodynamics with a Spin Qubit
- Strong spin-photon coupling in silicon
- Semiconductor Qubits In Practice
- Fast Single-Charge Sensing with an rf Quantum Point Contact
- Low frequency admittance of a quantum point contact
- Quantum Point Contacts
- An off-board quantum point contact as a sensitive detector of cantilever motion
- Quantum nondemolition measurement of an electron spin qubit
- Sensitive radio-frequency measurements of a quantum dot by tuning to perfect impedance matching
- Clean carbon nanotubes coupled to superconducting impedance-matching circuits
- Repetitive quantum non-demolition measurement and soft decoding of a silicon spin qubit
- Realization of GHz-frequency impedance matching circuits for nano-scale devices
- Shot noise of a quantum dot measured with GHz stub impedance matching
- Optimization of sample-chip design for stub-matched radio-frequency reflectometry measurements
- Wigner Function Description of the A.C.-Transport Through a Two-Dimensional Quantum Point Contact