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Superluminal geometrical resonances observed in Bi2Sr2CaCu2O8+x intrinsic Josephson junctions

S. O. Katterwe, A. Rydh, H. Motzkau, A. B. Kulakov, V. M. Krasnov

DOI 10.1103/PhysRevB.82.024517 · Physical Review B

T1

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Abstract

We study Fiske steps in small Bi2Sr2CaCu2O8+x mesa structures, containing only a few stacked intrinsic Josephson junctions. Careful alignment of magnetic field prevents penetration of Abrikosov vortices and facilitates observation of a large variety of high-quality geometrical resonances, including superluminal with velocities larger than the slowest velocity of electromagnetic waves. A small number of junctions limits the number of resonant modes and allows accurate identification of modes and velocities. It is shown that superluminal geometrical resonances can be excited by subluminal fluxon motion and that flux flow itself becomes superluminal at high magnetic fields. We argue that observation of high-quality superluminal geometrical resonances is crucial for realization of the coherent flux-flow oscillator in the terahertz frequency range.

Source-reported materials — not catalogue approval

FormulaReported Tc (K)Pressure (GPa)Type
Bi2Sr2CaCu2O8+x

Archive — visibility unverified

Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.

82Pressure not reportedunknown
Bi2Sr2CaCu2O8+x

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Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.

89Pressure not reportedunknown
Bi2-yPbySr2CaCu2O8+x

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Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.

87Pressure not reportedunknown

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