Shapiro steps in Josephson Junctions
نویسنده
چکیده
We use Ginzburg-Landau theory to describe the phase transition to the superconducting state and the current through a superconductor. Applying quantum mechanics to the Josephson junction following Feynmann’s method the Josephson relations for AC and DC current through the junctions is obtained. The resistively shunted Josephson junction and the resistively and capacitively shunted Josephson junction are analyzed. When subject to an alternating voltage driven circuit Shapiro spikes occur in the I vs. V characteristics of the circuit. If the circuit is driven by an AC current Shapiro steps appear with jumps when the average voltage is an integer multiplum of the frequency times the Josephson constant. Vi anvender Ginzburg-Landau teori til at beskrive faseovergangen til det superledende fase, og strømmen gennem en superleder. Ved brug af kvantemekanik p̊a en Josephson junction findes ud fra Feynmann’s metode Josephson relationerne for AC of DC strømme gennem junctionen. Josephson junctionen med modstand og Josephson junctionen med modstand of capacitans analyseres. Når kredsløbene bliver drevet med en vekselstrøm opst̊ar Shapiro spikes i I vs. V karakteristikken. Hvis kredsløbet drives med en vekselstrøm fremkommer Shapiro steps med hop n̊ar then gennemsnitlige spænding er et integer multiplum af frekvensen multipliceret med Josephson konstanten.
منابع مشابه
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