Microscopic relaxation channels in materials for superconducting qubits

Title	Microscopic relaxation channels in materials for superconducting qubits
Authors	Anjali Premkumar, Conan Weiland, Sooyeon Hwang, Berthold Jäck, Alexander P. M. Place, Iradwikanari Waluyo, Adrian Hunt, Valentina Bisogni, Jonathan Pelliciari, Andi Barbour, Mike S. Miller, Paola Russo, Fernando Camino, Kim Kisslinger, Xiao Tong, Mark S. Hybertsen, Andrew A. Houck, Ignace Jarrige
Magazine	Communications Materials
Date	07/01/2021
DOI	10.1038/s43246-021-00174-7
Introduction	The study addresses the significant challenge posed by material imperfections in the application of superconducting qubits. By correlating transmon qubit relaxation times with the properties of polycrystalline niobium films, the research identifies connections between qubit coherence and intrinsic film characteristics such as grain size, oxygen diffusion along grain boundaries, and surface suboxide concentration. Films deposited by different methods reveal how these factors influence qubit performance. Evidence suggests two-level system defects may reside in grain boundaries and surface oxides. The residual resistance ratio of the films emerges as a metric for assessing qubit longevity, paving the way for enhancing superconducting qubit performance through material improvements.
Quote	Anjali Premkumar, Conan Weiland and Sooyeon Hwang et al. Microscopic relaxation channels in materials for superconducting qubits. Commun Mater. 2021. Vol. 2(1). DOI: 10.1038/s43246-021-00174-7
Element	Niobium (Nb) , Oxygen (O)
Materials	Metals and Alloys , Oxides
Topics	Deposition Processes
Industry	Electronics