8 papers
Oxide-nitride heteroepitaxy for low-loss dielectrics in superconducting quantum circuits
David A. Garcia-Wetten, Mitchell J. Walker, Peter G. Lim +9
Superconducting qubits show great promise for the realization of fault-tolerant quantum computing, but lossy, amorphous dielectrics limit current technology. Identifying highly cry…
Effect of metal encapsulation on bulk superconducting properties of niobium thin films used in qubits
Amlan Datta, Kamal R. Joshi, Sunil Ghimire +18
Niobium metal occupies nearly 100\% of the volume of a typical 2D transmon device. While the aluminum Josephson junction is of utmost importance, maintaining quantum coherence acro…
Oxygen distribution and segregation at grain boundaries in Nb and Ta-encapsulated Nb thin films for superconducting qubits
Jaeyel Lee, Dieter Isheim, Zuhawn Sung +14
We report on atomic-scale analyses of oxygen distribution and segregation at grain boundaries (GBs) of Nb and Ta-encapsulated Nb (Ta/Nb) thin films for superconducting qubits using…
Comparison of Nb and Ta Pentoxide Loss Tangents for Superconducting Quantum Devices
D. P. Goronzy, W. W. Mah, P. G. Lim +14
Superconducting transmon qubits are commonly made with thin-film Nb wiring, but recent studies have shown increased performance with Ta wiring. In this work, we compare the resonat…
Vortex-Controlled Quasiparticle Multiplication and Self-Growth Dynamics in Superconducting Resonators
Joong M. Park, Martin Mootz, Richard H. J. Kim +11
Even in the quantum limit, non-equilibrium quasiparticle (QP) populations induce QP poisoning that irreversibly relaxes the quantum state and significantly degrades the coherence o…
Identifying Materials-Level Sources of Performance Variation in Superconducting Transmon Qubits
Akshay A. Murthy, Mustafa Bal, Michael J. Bedzyk +46
The Superconducting Materials and Systems (SQMS) Center, a DOE National Quantum Information Science Research Center, has conducted a comprehensive and coordinated study using super…