Wideband superconducting nanotube electrometer

Autor: Häkkinen, Pasi, Fay, Aurélien, Golubev, Dmitry, Lähteenmäki, Pasi, Hakonen, Pertti
Rok vydání: 2015
Předmět:
Zdroj: Applied Physics Letters 107, 012601 (2015)
Druh dokumentu: Working Paper
DOI: 10.1063/1.4926400
Popis: We have investigated the microwave response of nanotube Josephson junctions at 600-900 MHz at microwave powers corresponding to currents from 0 to $2\times I_{\mathrm C}$ in the junction. Compared with theoretical modeling, the response of the junctions correspond well to the lumped element model of resistively and capacitively shunted junction. We demonstrate the operation of these superconducting FETs as charge detectors at high frequencies without any matching circuits. Gate-voltage-induced charge $Q_{\rm G}$ modifies the critical current $I_{\rm C}$, which changes the effective impedance of the junction under microwave irradiation. This change, dependent on the transfer characteristics $dI_{\mathrm C}/dQ_{\rm G}$, modifies the reflected signal and it can be used for wide band electrometry. We measure a sensitivity of $3.1\times10^{-5}$ $e/\sqrt{\mathrm{Hz}}$ from a sample which has a maximum switching current of 2.6 nA.
Comment: 4 pages, 4 figures
Databáze: arXiv