7-11 July 2014
Africa/Johannesburg timezone
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Can Shapiro step subharmonics be "charged"?

Presented by Dr. Hermann AZEMTSA DONFACK on 10 Jul 2014 from 14:40 to 15:00
Type: Oral Presentation
Session: DPCMM1
Track: Track A - Division for Physics of Condensed Matter and Materials


The system of superconducting layers found in high temperature superconductors (HTSC) such as Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>{8+&delta}</sub> (Bi-2122) represent intrinsic Josephson junctions (IJJs). The locking of the Josephson oscillations (&omega<sub>J</sub>) of each junction of the IJJ to the frequency (&omega<sub>ext</sub>) of external electromagnetic radiation leads to the appearance at quantized voltages of the so-called Shapiro steps in the current voltage characteristics (IV-characteristics). Many devices in existence exploit this effect, notably voltage standards. Therefore, a detailed study of the Shapiro steps and their subharmonics in the intrinsic Josephson junctions at different resonance conditions presents important research questions with potential for different applications. Using the capacitively coupled Josephson junction with diffusion current (CCJJ + DC model), we performed precise numerical study of phase dynamics of intrinsic Josephson junctions under external electromagnetic radiation. We survey the different Shapiro steps (SS) subharmonics found in these systems. We establish a link between the "charging" of superconducting layers in bias-current interval corresponding to SS subharmonics, and the existence of longitudinal plasma waves (LPW) in the system.








Room: D Les 201

Primary authors