Time Dependence of Partial Integrated Charge Fluctuations in Superconducting Tunnel Junctions (STJs)

Superconducting tunnel junction is used as a high-speed, high-resolution detector for X-ray spectroscopy. The superconducting tunnel junction (STJ) consists of two superconducting layers separated by a thin insulating barrier. Is the interstitial energy of the superconducting material and is the fundamental charge, STJ can be used as a detector for voltage bias junctions. In the interaction with the superconducting electrode, the X-ray quantum generates excessive unbalanced quasiparticles. Each quasiparticle of a superconductor is a quantum superposition of excitations such as electrons and holes.

In several years, superconducting tunnel junction detectors (STJ) may be a viable alternative to CCD (charge coupled device) for astronomy and astrophysics. These devices are effective over a wide range from ultraviolet to infrared and X-rays. This technology has been tested on the SCAM device William Herschel telescope. The voltage and current through the Josephson junction are the "phase difference" of the entire junction (ie the difference in phase coefficient between the two superconductors of the Ginzburg-Landau complex order parameter, or equivalently the parameter). And constant, junction "critical current". Critical current is an important phenomenological parameter of a device that may be affected by temperature and applied magnetic field. Physical constant is flux quantum, its reciprocal is Josephson constant.

The Josephson junction is a quantum mechanical device consisting of two superconducting electrodes separated by a barrier (thin insulating tunnel barrier, common metal, semiconductor, ferromagnet etc). The π Josephson junction is a Josephson junction whose Josephson's phase φ is equal to π in the ground state, that is, when no external current or magnetic field is applied. The supercurrent Is (JJ) through the Josephson junction is usually given by Is = I c sin (φ), where φ is the phase difference of the superconducting wave function of the two electrodes, ie the Josephson phase. The critical current Ic is the maximum overcurrent that can flow through the Josephson junction. In the experiment some current is normally applied through the Josephson junction and the junction responds by changing the Josephson phase. As can be seen from the above equation, the phase φ = arcsin (I / Ic), where I is the applied (super) current.