Berlin 2012 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
TT: Fachverband Tiefe Temperaturen
TT 46: Superconductivity: Tunnelling, Josephson Junctions, SQUIDs 2
TT 46.2: Talk
Thursday, March 29, 2012, 18:00–18:15, H 2053
Quantum phase slip interference device based on a shaped superconducting nanowire — •Alexander Zorin and Terhi Hongisto — Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany
As was predicted by Mooij and Nazarov, the superconducting nanowires may exhibit, depending on the impedance of external electromagnetic environment, not only quantum slips of phase, but also the quantum-mechanically dual effect of coherent transfer of single Cooper pairs. We propose and realize a transistor-like superconducting circuit including two serially connected segments of a narrow (10nm by 18nm) nanowire joint by a wider segment with a capacitively coupled gate in between. This circuit is made of amorphous NbSi film and embedded in a network of on-chip Cr microresistors ensuring a high external impedance (≫ h/e2 ≈ 25.8 kΩ) and, eventually, a charge bias regime. Virtual quantum phase slips in two narrow segments of the wire lead in this case to quantum interference of voltages on these segments making this circuit dual to the dc SQUID. Our samples demonstrated appreciable Coulomb blockade voltage (analog of critical current of the SQUID) and remarkable periodic modulation of this blockade by an electrostatic gate (analog of flux modulation in the SQUID). The obtained experimental results and the model of this QPS transistor will be presented.