Characterization of Asymmetric Gap-Engineered Josephson Junctions and 3D Transmon Qubits
arXiv:2302.12280 · doi:10.1109/TASC.2023.3247987
Abstract
We have fabricated and characterized asymmetric gap-engineered junctions and transmon devices. To create Josephson junctions with asymmetric gaps, Ti was used to proximitize and lower the superconducting gap of the Al counter-electrode. DC IV measurements of these small, proximitized Josephson junctions show a reduced gap and larger excess current for voltage biases below the superconducting gap when compared to standard Al/AlOx/Al junctions. The energy relaxation time constant for an Al/AlOx/Al/Ti 3D transmon was T1 = 1 μs, over two orders of magnitude shorter than the measured T1 = 134 μs of a standard Al/AlOx/Al 3D transmon. Intentionally adding disorder between the Al and Ti layers reduces the proximity effect and subgap current while increasing the relaxation time to T1 = 32 μs.
arXiv comment5 pages, 3 figures, to be published in IEEE Transactions on Applied Superconductivity
References in corpus (24)
- Circuit Quantum Electrodynamics: Coherent Coupling of a Single Photon to a Cooper Pair Box
- A Quantum Engineer's Guide to Superconducting Qubits
- Superconducting Qubits: Current State of Play
- Decoherence in Josephson Qubits from Dielectric Loss
- New material platform for superconducting transmon qubits with coherence times exceeding 0.3 milliseconds
- AC JOSEPHSON EFFECT IN A SINGLE QUANTUM CHANNEL
- Transmon qubit with relaxation time exceeding 0.5 milliseconds
- Correlated Charge Noise and Relaxation Errors in Superconducting Qubits
- Millisecond charge-parity fluctuations and induced decoherence in a superconducting qubit
- Nonequilibrium quasiparticles and periodicity in single-Cooper-pair transistors
- Hot non-equilibrium quasiparticles in transmon qubits
- Determining interface dielectric losses in superconducting coplanar waveguide resonators
- Non-Poissonian Quantum Jumps of a Fluxonium Qubit due to Quasiparticle Excitations
- Evidence of a nonequilibrium distribution of quasiparticles in the microwave response of a superconducting aluminium resonator
- Measurements of Quasiparticle Tunneling Dynamics in a Bandgap-Engineered Transmon Qubit
- Reducing quantum-regime dielectric loss of silicon nitride for superconducting quantum circuits
- Superconductive properties of thin dirty SN bilayers
- Environmental Radiation Impact on Lifetimes and Quasiparticle Tunneling Rates of Fixed-Frequency Transmon Qubits
- Energy gap measurement of nanostructured thin aluminium films for use in single Cooper-pair devices
- A generalized proximity effect model in superconducting bi- and tri-layer films
- Quasiparticles in superconducting qubits with asymmetric junctions
- Parity effect in superconducting aluminum single electron transistors with spatial gap profile controlled by film thickness
- Dynamics of parametric fluctuations induced by quasiparticle tunneling in superconducting flux qubits
- Calculation and measurement of critical temperature in thin superconducting multilayers