Center for Functional Nanomaterials Seminar

Advancing quantum materials and devices research requires efficient probes sensitive to local electrodynamic properties. Scanning microwave microscopy (SMM) is an advantageous tool, offering high spatial resolution, minimal sample preparation requirements, and frequency compatibility with leading quantum hardware such as superconducting qubits. In this talk, I will introduce two seminal advancements in SMM probes for probing quantum materials and devices. First, we have implemented a dilution-refrigerator-based microwave impedance microscopy (MIM) system that enables nanoscale measurements of permittivity and conductivity at milli-Kelvin temperatures. This capability is crucial for investigating ultralow-energy quantum materials physics that are fragile at higher temperatures. Second, by incorporating a high-Q superconducting resonator into a milli-Kelvin SMM platform, we have achieved high-sensitivity microwave imaging in the few-photon regime, allowing for coherent probing of quantum devices with minimized hardware overhead. To demonstrate this capability, we used our scanning resonator setup to characterize the energy spectrum and coherence times of multiple transmon qubits without on-chip readout circuits. I will conclude with an outlook on addressing materials challenges in quantum information hardware through the combined use of advanced scanning microwave probes at ultralow temperatures.