Designing a Cavity-Embedded Cooper Pair Transistor for Single Electron Resolution Charge Sensing on Novel Narrow Gap Semiconductors

Both HEP and quantum computing experiments use single electron-sensitive charge amplifiers. In HEP, various groups achieved single electron sensitivity using complex fabrication techniques with specific detector designs, e.g., Skipper CCDs (Si) and SuperCDMS HVeV (Si, Ge). In quantum computing, devices such as RF-SETs, which require large readout power, have measured single electrons in quantum dots and monitored quasiparticle tunneling in superconducting systems. The cavity-embedded Cooper pair transistor (cCPT) is a superconducting quantum device that requires low readout power near the single photon level. With cCPTs, we are developing a single electron-sensitive charge amplifying device that will couple to various novel semiconductor substrates, e.g., Eu₅In₂Sb₆ grown by the SPLENDOR collaboration. While our primary use is for low-mass dark matter detection, this cCPT device can additionally benefit the quantum computing field by monitoring parasitic charge events from particle interactions in the substrate that are a problematic source of decoherence in superconducting qubits. This poster presentation will discuss the cCPT's design, modeling, and results from the first round of fabricated devices. The presentation will also contrast the cCPT's expected performance with a conventional HEMT-based charge amplifier developed by the SPLENDOR experiment for 10mK charge detection.