Microwave response in a topological superconducting quantum interference device

Abstract

Photon detection at microwave frequency is of great interest due to its application in quantum computation information science and technology. Herein are results from studying microwave response in a topological superconducting quantum interference device (SQUID) realized in Dirac semimetal Cd3As2. The temperature dependence and microwave power dependence of the SQUID junction resistance are studied, from which we obtain an effective temperature at each microwave power level. It is observed the effective temperature increases with the microwave power. This observation of large microwave response may pave the way for single photon detection at the microwave frequency in topological quantum materials.

Leggett Modes in Dirac Semimetals

“…Fabrication. Mechanical exfoliation is used to obtain flat and shiny Cd 3 As 2 thin flakes of thickness ∼200 nm from an initial bulk ingot material 30 , synthesized via a chemical vapor deposition method 36 . The SQUID structure is fabricated by first depositing the Cd 3 As 2 thin flake on a Si/SiO 2 substrate with a 1 µm thick SiO 2 layer.…”

“…In a Dirac semimetal (DSM) the bulk 3D conduction and valence electronic bands touch at isolated points, and a projection of the spectral density onto a surface BZ reveals Fermi arcs connecting the bulk Dirac points 25,26 . DSM's with proximity-induced superconductivity are predicted to be able to realize exotic non-Abelian anyons that can used to develop topologically-protected qubits 27 and can be used in microwave single-photon detection for sensing applications [28][29][30] . Another aspect DSMs that has received less attention in the literature concerns the multiband properties of superconducting DSMs 31,32 .…”

Leggett modes in a Dirac semimetal

“…Mechanical exfoliation is used to obtain flat and shiny Cd 3 As 2 thin flakes of thickness ~200 nm from an initial bulk ingot material 29 , synthesized via a chemical vapour deposition method 36 . The SQUID structure is fabricated by first depositing the Cd 3 As 2 thin flake on a Si/SiO 2 substrate with a 1-μm-thick SiO 2 layer.…”

“…In a DSM such as Cd 3 As 2 , the bulk three-dimensional conduction and valence electronic bands touch at isolated points, and a projection of the spectral density onto a surface Brillouin zone reveals Fermi arcs connecting the bulk Dirac points 24,25 . DSMs with proximity-induced superconductivity are predicted to be able to realize exotic non-Abelian anyons that can be used to develop topologically protected qubits 26 and can be used in microwave single-photon detection for sensing applications [27][28][29] . Another aspect of DSMs that has received less attention in the literature concerns the multiband properties of superconducting DSMs [30][31][32] .…”