Phase dynamics and electrodynamics in intrinsic Josephson junctions of cuprate high-T[c] superconductors
Year: 2010
Type: dissertation
Abstract: 論 文 の 内 容 の 要 旨 Electromagnetic (EM) waves in the terahertz (THz) frequency band have many important applications, such as DNA diagnosis, telecommunication and materials characterization.Nevertheless, they are difficult to generate by either electronic or photonic technique.To develop strong and compact solid-state source of THz EM wave is a big challenge.A Josephson junction is a natural dc-to-ac converter.As Cooper pairs tunnel back and forth across the junction under a dc bias voltage, Josephson plasma oscillations are excited, which then radiate a part of the energy into space in the form of EM wave.The radiation frequency and the bias voltage follow the ac Josephson relation; quantitatively, a bias voltage of l meV corresponds to 0.483 THz.However, the radiation power from a single junction is too small for practical applications and the frequency is around 100GHz limited by the small superconducting energy gap.The discovery of the intrinsic Josephson effect in cuprate high-Tc superconductors, such as Bi 2 Sr 2 CaCu 2 O 8+δ (BSCCO), provides a possibility to develop strong sources of THz EM waves.Due to the layered structure of crystal the superconductivity is strongly modulated along the c axis, and thus a BSCCO single crystal forms a stack of intrinsic Josephson junctions (IJJs).The advantages of IJJs are: l) the superconductivity gap is about 60 meV which supports operating frequency as high as 10THz without severe damping; 2) all junctions are almost identical; 3) there is a huge
Author: 士増 林
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2282263122