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Hybrid superconducting circuit made with van der Waals heterostructures
Wang, Joel J. - Massachusetts Institute of Technology
Presentation on Thursday, Nov. 21, 2019, noon
Location: MIT Room 6C-442
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Van der Waals (vdW) materials – a family of layered crystals - including semi-metals, insulators, semiconductors, ferromagnets, superconductors, and topological insulators - can be assembled in specific arrangements to create new electronic devices called vdW heterostructures. The extraordinary and versatile electronic properties of these heterostructures, in combination with their epitaxial precision, make vdW-based devices a promising alternative for constructing key elements of novel solid-state quantum computing platforms.
This talk will address our recent works on vdW materials of relevance to superconducting quantum technology. We demonstrate quantum coherent control of a superconducting circuit incorporating graphene-based vdW heterostructures. This device can be operated as a voltage-tunable transmon qubit, whose spectrum reflects the unique electronic properties of massless Dirac fermions traveling ballistically. We also study the microwave loss of hexagonal boron nitride (hBN), a layered, crystalline insulator widely used in building vdW heterostructures, by coupling this material to an LC oscillator. In the low-temperature, single-photon limit, the quality factor of hBN is shown to be at least 200,000. The demonstrated experimental techniques can be applied to study a wide range of vdW materials for applications as well as the physics therein.